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33 questions · timed · auto-graded

Question 13 Marks
The present population of a town is $1,15200.$ If it increases at the rate of $6 \frac{2}{3} \%$ per annum , find Its population after $2$ years
Answer
$ V_n=7 \cdot V_o=115200 ; r=6 \frac{2}{3} \%=20 / 3 \% ; t=2 \text { years }$
$V_n=V_0 \times\left(1+\frac{r}{100}\right) $
$ V_n=115200\left(1+\frac{20}{100 \times 3}\right)^2 $
$ V_n 1,15,200 \times 1.06667 \times 1.06667 $
$ V_n=1,31,072 $
The population $2$ years later $=1,31,072$
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Question 23 Marks
The cost of a T.V. was quoted $Rs.17,000$ at the beginning of the year $1999.$ In the beginning of $2000$ the price was hiked by $5\%.$ Because of decrease in demand the cost was reduced by $4\%$ in the beginning of $2001.$ What is the cost of the T.V. in $2001?$
Answer
$V _{ n }=? ; V _0= Rs 17,000 ; t =2$ years ( 1 for increment and 1 for decrement); $r=5 \%$ tor increase and $4 \%$ tor decrease.
$V_n=V_0\left(1+\frac{r}{100}\right)^n\left(1-\frac{r}{100}\right)^n$
$ V_n=\operatorname{Rs} 17000\left(1+\frac{5}{100}\right)\left(1-\frac{4}{100}\right) $
$ V_n=\operatorname{Rs~} 17,000 \times 1.05 \times 0.96$
$ V_n=\operatorname{Rs~} 17136$
The cost of the T.V. in $2001$ is Rs $17,136$.
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Question 33 Marks
What sum of money will amount to $Rs.8,073$ in $2$ years at compound interest if the rates of interest for the successive years are $15\%$ and $17\%?$
Answer
Here $P=? ; t=2$ years; $r=15 \%$ and $17 \%$ successively;
$A=\text { Rs } 8,073$
$A=P\left(1+\frac{r}{100}\right)^n $
$ \text { Rs } 8073= P \left(1+\frac{15}{100}\right)\left(1+\frac{17}{100}\right) $
Rs $8,073=P \times 1.15 \times 1.17$
Rs $8,073=1.3455 P$
$ P=R s \frac{8073}{13455} $
$ P=\operatorname{Rs} 6,000 $
Hence, the sum of money is $Rs.6,000$
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Question 43 Marks
Calculate the amount and the compouncl interest of the following:
$Rs.9,125$ for $2$ years if tl1e rates of interest are $12\%$ and $14\%$ for the successive years.
Answer
$P=\operatorname{Rs} 9,125 ; t=2$ years $; r=12 \%$ and $14 \%$
successively.
$A=P\left(1+\frac{r}{100}\right)^n$
$ A=\text { Rs } 9125\left(1+\frac{12}{100}\right)\left(1+\frac{14}{100}\right)$
$=\text { Rs } 9,125 \times 1.12 \times 1.14 $
$=\text { Rs } 11,650.80$
$ \text { C.I. }=A-P$
$=\text { Rs }(11,650.80-9,125)$
$=\text { Rs 2,525.80 } $
Hence, Amount $= Rs.11,650.80$ and C.I. $=Rs.2,525.80$
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Question 53 Marks
Calculate the amount and the compound interest for the following, when cornpounded half-yearly:
$Rs.25,000$ for $1 \frac{1}{2}$ years at $12 \%$
Answer
$P=\operatorname{Rs} 25,000 ; t=1 \frac{1}{2}$ years $; r=12 \%$ p.a. $=6 \%$ half-early.
$A=P\left(1+\frac{r}{100}\right)^n $
$A=\operatorname{Rs} 25000\left(1+\frac{6}{100}\right)^2\left(1+\frac{12}{100}\right)^{\frac{1}{2}} $
$ =\text { Rs } 25,000 \times 1.06 \times 1.06 \times\left(1+\frac{1}{2} \times \frac{12}{100}\right)$
$=\text { Rs } 25,000 \times 1.06 \times 1.06 \times 1.06 $
$=\text { Rs29,775.40 } \\ \text { C.I. }=A-P $
$=\text { Rs }(29,775.40-25,000) $
$ =\text { Rs } 4,775.40$
Hence, Amount $= Rs.29,775.40$ and C.I. $=Rs.4,775.40$
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Question 63 Marks
Calculate the amount and the compound interest for the following, when cornpounded half-yearly:
$Rs.6,000$ for $1 \frac{1}{2}$ years at $10 \%$ p.a.
Answer
$Rs.6,000$ for $1 \frac{1}{2}$ years at $10 \%$ p.a.
$P=Rs.6,000 ; t=1 \frac{1}{2}$ years $; r=10 \%$ p.a. $=5 \%$
half-yearly.
$A=P\left(1+\frac{r}{100}\right)^n$
$A=\operatorname{Rs} 6000\left(1+\frac{5}{100}\right)^2\left(1+\frac{10}{100}\right)^{\frac{1}{2}}$
$=\text { Rs } 6000 \times 1.05 \times 1.05 \times\left(1+\frac{1}{2} \times \frac{10}{100}\right)$
$=\text { Rs } 61000 \times 1.05 \times 1.05 \times 1.05$
$=\text { Rs } 6945.75$
$\text { C.I. }=A-P$
$=\text { Rs }(6,945.75-6,000)$
$=\text { Rs } 945.75$
Hence, Amount $= Rs.6,945.75$ and C.I. $=Rs.945.75$
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Question 73 Marks
Calculate the amount and cornpound interest for the following, when cornpounded annually:
$Rs.7,500$ for $2 \frac{1}{2}$ years ; $r=16 \%$ p.a.
Answer
$P=\operatorname{Rs} 7,500 ; t=2 \frac{1}{2} \text { years } ; r=16 \% \text { p.a. } $
$A=P\left(1+\frac{r}{100}\right)^n$
$ A=\operatorname{Rs} 7500\left(1+\frac{16}{100}\right)^2\left(1+\frac{16}{100}\right)^{\frac{1}{2}} $
$=\operatorname{Rs} 7500 \times 1.16 \times 1.16 \times\left(1+\frac{1}{2} \times \frac{16}{100}\right) $
$=\text { Rs } 7,500 \times 1.16 \times 1.16 \times 1.08 $
$ =\text { Rs } 10,899.36 \\ \text { C.I. }=A-P$
$ =\text { Rs }(10,899.36-7,500) $
$=\text { Rs } 3,399.36 $
Hence, Amount $= Rs.10,899.36$ and C.I. $=Rs.3,399.36$
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Question 83 Marks
Calculate the amount and cornpound interest for the following, when cornpounded annually:
$Rs.8,000$ for $1 \frac{1}{2}$ years at $12 \%$ p.a.
Answer
$P=\operatorname{Rs} 8,000 ; t=1 \frac{1}{2} \text { years } ; r=12 \% \text { p.a. }$
$ A=P\left(1+\frac{r}{100}\right)^{ n } $
$ A=\operatorname{Rs} 8000\left(1+\frac{12}{100}\right)\left(1+\frac{12}{100}\right)^{\frac{1}{2}}$
$=\text { Rs } 8000 \times 1.12 \times\left(1+\frac{1}{2} \times \frac{12}{100}\right) $
$=\text { Rs } 8,000 \times 1.12 \times 1.06$
$=\text { Rs } 9,497.60$
$ \text { C.I. }=\text { A }-P$
$=\operatorname{Rs}(9,497.60-8,000) $
$=\operatorname{Rs~} 1,497.60$
Hence, Amount $= Rs.9,497.60$ and C.I. $=Rs.1,497.60$
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Question 93 Marks
Calculate the amount and cornpound interest for the following, when cornpounded annually:
$Rs.16,000$ for $3$ years at $7 \frac{1}{2} \%$ p.a.
Answer
$Rs.16,000$ for $3$ years at $7 \frac{1}{2}$ p.a.
$P=\operatorname{Rs} 16,000 ; t=3$ years $; r=7 \frac{1}{2}$ p.a.
$A=P\left(1+\frac{r}{100}\right)^n $
$A=\text { Rs } 16000\left(1+\frac{15}{2 \times 100}\right)^3$
$=\text { Rs } 16,000 \times 1.075 \times 1.075 \times 1.075 $
$=\text { Rs } 19,876.75$
$ \text { C.I. }=A-P $
$ =\text { Rs }(19,876.75-16,000) $
$ =\text { Rs 3,876. } 75 $
Hence, Amount $= Rs.19,876.75$ and C.I. $= Rs.3,876.75$
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Question 103 Marks
Calculate the amount and cornpound interest for the following, when cornpounded annually:
Rs 25,000 for 3 years at 8 % p.a.
Answer
Rs 25,000 for 3 years at $8 \%$ p.a.
$P=R s 25,000 ; t=3$ years; $r=8 \%$ p.a.
$ A = P \left(1+\frac{ r }{100}\right)^{ n } $
$ A=\operatorname{Rs} 25000\left(1+\frac{8}{100}\right)^3 $
$ =\text { Rs } 25,000 \times 1.08 \times 1.08 \times 1.08 $
$ =\text { Rs } 31,492.80 $
C.I $= A - P$
$ =\operatorname{Rs}(31,492.80-25,000) $
$ =\text { Rs 6,492.80 } $
Hence, Amount $=$ Rs 31,492.80 and C.I. $=$ Rs 6,492.80
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Question 113 Marks
Calculate the Amount and Cornpound Interest for the Following, when Cornpounded Annually:
$Rs.12,000$ for $3$ years at $15\%$ p.a.
Answer
$Rs.12,000$ for $3$ years at $15 \%$ p.a.
$ P=\text { Rs } 12,000 ; t=3 \text { years; } r=15 \% \text { p.a. } $
$A=P\left(1+\frac{r}{100}\right) $
$ A=\text { Rs } 12000\left(1+\frac{15}{100}\right)$
$=\text { Rs } 12000 \times 1.15 \times 1.15 \times 1.15 $
$ =\text { Rs } 18250.50$
$\text { C.I. }=A-P$
$ =\text { Rs }(18,250.50-12,000) $
$ =\text { Rs } 6,250.50 $
Hence. Amount $= Rs.18.250.50$ and C.I. $= Rs.6.250 .50$
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Question 123 Marks
Anand borrows $Rs.20,000$ at $9 \%$ p.a. simple interest for $3$ years. He immediately gave it to Prakash at $8 \frac{1}{2} \%$ p.a. compound interest compounded annually. Find Anand's loss or gain.
Answer
Here, $P=Rs.20,000 ; t=3$ years
For simple interest: $r=9 \%$
$\text { S.I. }=\frac{ P \times r \times t }{100} $
$ \text { S.I. }=\operatorname{Rs} \frac{20000 \times 9 \times 3}{100} $
$ \text { S.I. }=\operatorname{Rs} 5400$
For compound interest : $r=8 \frac{1}{2} \%$
$A=P\left(1+\frac{r}{100}\right)^n $
$ A=\text { Rs } 20000\left(1+\frac{17}{2 \times 100}\right)^3 $
$ A=\text { Rs } 20000 \times \frac{217}{200} \times \frac{217}{200} \times \frac{217}{200} $
$A=\text { Rs } 25545.70 \\ \text { C.I. = A - P } $
$ \text { C.I. = Rs (25,545.70 - 20,000) } $
$\text { C. I. = Rs 5,545.70 }$
The difference in the compound interest and the simple interest $= Rs.(5,545.705-400)= Rs.145.70$ Anand gained $Rs.145.70$
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Question 133 Marks
The simple interest and the compound interest on a certain sum of money for $2$ years at the same rate of interest are $Rs.8,000$ and $Rs.8,640$ respectively. Calculate the rate of interest and the sum.
Answer
The extra interest earned = C.I. - S.I. $=$ Rs $(8,640-$ $8,000)= Rs.640.$
The interest for the first year $=S$. I. for $2$ years $/ 2=$ Rs $\frac{8000}{2}= Rs.4000$
Therefore, the rate of interest $=\frac{640}{4000} \times 100=16 \%$
Now,
$\text { S.I. }=\frac{ P \times r \times t }{100}$
$ \Rightarrow Rs.8000=\frac{ P \times 16 \times 2}{100} $
$ \Rightarrow P=R s \frac{8000 \times 100}{32}$
$\Rightarrow P=\operatorname{Rs} 25000$
The rate of interest was $16 \%$ and the original sum was $Rs.25,000 .$
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Question 143 Marks
The simple interest on a certain sum in $2$ years is $Rs.1,300,$ whereas the compound interest on the same sum at the same rate and for the same time is $Rs.1,365.$ Find the rate per cent and the sum.
Answer
The extra interest earned = C. I. - S. I. $= Rs ( 1,365 - 1,300)=\text { Rs } 65 \text {. } $
The interest for the first year = S. I. for $2$ years $/ 2=$ Rs $ \frac{1300}{2}=\text { Rs } 650 $
Therefore, the rate of interest $=\frac{65}{650} \times 100=10 \%$
Now,
$ \text { S.I. }=\frac{P \times r \times t}{100}$
$\Rightarrow \text { Rs } 1300=\frac{P \times 10 \times 2}{100}$
$\Rightarrow P=\operatorname{Rs} 1300 \times 5$
$\Rightarrow P=\operatorname{Rs} 6500 $
The rate of interest was $10 \%$ and the original sum was Rs 6,500.
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Question 153 Marks
The cost of a machine dep reciated by $Rs.2592$ during the third year and by $Rs.2332.80$ during the fourth year. Calculate :
The cost at the end of the fourth year.
Answer
$\text { Here, } P=\text { Rs } 32,000 ; r=10 \% ; t=4 \text { years } $
$A=P\left(1+\frac{r}{100}\right)^n $
$ A=Rs.32000\left(1-\frac{10}{100}\right)^4 $
$ A=\text { Rs } 32,000 \times 0.9 \times 0.9 \times 0.9 \times 0.9$
$ A=\text { Rs } 20,995.20 $
$ \text { Cost at the end of the fourth year = Rs } 20,995.20$
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Question 163 Marks
The cost of a machine depreciated by Rs 2592 during the third year and by Rs 2332.80 during the fourth year. Calculate :
The rate of depreciation.
Answer
Difference in the depreciation $=\operatorname{Rs}(2,592-2,332.80)$ $=$ Rs 259.20
Rate of depreciation $=\frac{259.20}{2592} \times 100=10 \%$
Rate of depreciation $=10 \%$
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Question 173 Marks
The cost of a scooter depreciated by $Rs.5100$ during the second year and by $Rs.4,335$ during the third year. Calculate
Answer
The oost of the soooter at the end of the third year. Here, $P=\operatorname{Rs} 40,000 ; r=15 \% ; t=3$ years
$ A=P\left(1+\frac{r}{100}\right)^n$
$ A=\operatorname{Rs} 40000\left(1-\frac{15}{100}\right) $
$ A=\operatorname{Rs} 40,000 \times 0.85 \times 0.85 \times 0.85 $
$ A=\operatorname{Rs} 24,565 $
Cost of the soooter at the end of third year $=$ Rs $ 24,565 $
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Question 183 Marks
The cost of a scooter depreciated by Rs 5100 during the second year and by Rs 4,335 during the third year. Calculate

the rate of depreciatlon

Answer
The rate of depreciation. Difference in the depreciation $=\operatorname{Rs}(5,100-4,335)=$ Rs 765
Rate of depreciation $=\frac{765}{5100} \times 100=15 \%$
Rate of depreciation $=15 \%$
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Question 193 Marks
What sum of money will amount to $Rs.16,637.50$ in $3$ years at $10\%$ p.a. compound interest?
Answer
Here $P=x ; A=R s 16,637.50 ; t=3$ years $; r=10 \%$ p.a
$\therefore A = P \left(1+\frac{ r }{100}\right)^{ n } $
$ \Rightarrow Rs 16637.50= x \left(1+\frac{10}{100}\right)^3 $
$ \Rightarrow Rs 16637.50= x \left(\frac{11}{10}\right)^3 $
$ \Rightarrow \operatorname{Rs} 16637.50= x \times \frac{11}{10} \times \frac{11}{10} \times \frac{11}{10}$
$ \Rightarrow \operatorname{Rs} 16637.50= x \times \frac{1331}{1000} $
$ \Rightarrow x =\operatorname{Rs} \frac{16637.50 \times 1000}{1331} $
$\Rightarrow x =\operatorname{Rs} 12500 $
The sum of money will be $Rs.12,500 .$
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Question 203 Marks
What sum of money will amount to $Rs.9,447.84$ in $3$ years at $8\%$ p.a. compound interest?
Answer
Here $P=x ; A=Rs.9,447.84 ; t=3$ years; $r=8 \%$ p.a
$ \therefore A = P \left(1+\frac{ r }{100}\right)^{ n } $
$ \Rightarrow Rs.9447.84= x \left(1+\frac{8}{100}\right)^3 $
$ \Rightarrow \operatorname{Rs} 9447.84= x \left(\frac{108}{100}\right)^3 $
$\Rightarrow \operatorname{Rs} 9447.84= x \times \frac{27}{25} \times \frac{27}{25} \times \frac{27}{25}$
$\Rightarrow \operatorname{Rs} 9447.84= x \times \frac{19683}{15625} $
$ \Rightarrow x =\operatorname{Rs} \frac{9447.84 \times 15625}{19683}$
$\Rightarrow x =\operatorname{Rs} 7500$
The sum of money will be $Rs.7,500.$
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Question 213 Marks
The value of a machine depreciates by $10\%, 12\%$ and $15\%$ in the first $3$ years. Express the total depreciation of the machine as a single per cent during the three years.
Answer
Let value of machine be Rs $x$.
$V_0=R s x ; n=3 ; r=10 \%$ for first year, $12 \%$
for $2$ nd year and $15 \%$ for $3$rd year
$\therefore V _{ t }= V _0 \times\left(1-\frac{ r }{100}\right)^{ n }$
$ \Rightarrow V _{ t }= Rs \times\left(1-\frac{10}{100}\right)\left(1-\frac{12}{100}\right)\left(1-\frac{15}{100}\right) $
$ \Rightarrow V _{ t }= Rs \times \frac{9}{10} \times \frac{22}{25} \times \frac{17}{20}$
$ \Rightarrow V _{ t }= Rs \times \frac{3366}{5000} $
$\Rightarrow V _{ t }=\text { Rs. } 0.6732 x$
Depreciation in the value of car
$ =\operatorname{Rs}(x-0.6732 x)=\operatorname{Rs} 0.3268 x $
Percentage change in depreciation
$ =\frac{0.3268 x }{ x } \times 100$
$=32.68 \%$
Percentage change $=32.68 \%$
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Question 223 Marks
The value of a car depreciated by $10\%$ in the first $2$ years and by $8\%$ in the third year. Express the total depreciation of the car as a single per cent during the three years.
Answer
Let value of car be Rs $x$.
$V_0=R s\  x ; n=3 ; r=10 \%$ for first $2$ years and $8 \%$ for $3$rd year.
$ \therefore V _{ t }= V _0 \times\left(1-\frac{ r }{100}\right)^{ n } $
$ \Rightarrow V _{ t }= Rs\ x \times\left(1-\frac{10}{100}\right)^2\left(1-\frac{8}{100}\right) $
$ \Rightarrow V _{ t }= Rs\ x \times \frac{9}{10} \times \frac{9}{10} \times \frac{23}{25} $
$ \Rightarrow V _{ t }= Rs\ x \times \frac{1863}{2500} $
$ \Rightarrow V _{ t }=\operatorname{Rs} 0.7452 x $
Depreciation in the value of car
$ =\operatorname{Rs}(x-0.7452 x)=\operatorname{Rs} 0.2548 x $
Percentage change in depreciation
$=\frac{0.2548 x }{ x } \times 100$
$ =25.48 \%$
Percentage change $=25.48 \%$
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Question 233 Marks
Prerna borrowed $Rs.16000$ from a friend at $15\%$ p.a. compound interest. Find the amount , to the nearest rupees, that she needs to return at the end of $2.4$ years to clear the debt.
Answer
$C _1=\frac{16000 \times 15 \times 1}{100}=2400 $
$P _1=18400 $
$ C _2=\frac{18400 \times 15 \times 1}{100}=2760$
$ P _2=21160 $
$ C _3=\frac{21160 \times 15 \times 1}{400}=7935 $
$ P _3=29095$
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Question 243 Marks
Natasha gave $Rs.60,000$ to Nimish for $3$ years at $15\%,$ p.a. compound interest.
Calculate to the nearest rupee :
The amount Natasha receives at the end of $3$ years.
Answer
$ C _1=\frac{60000 \times 15 \times 1}{100}=9000 $
$ P _1=69000$
$ C _2=\frac{69000 \times 15 \times 1}{100}=10350 $
$ P _2=79350 $
$ C _3=\frac{79350 \times 1 \times 15}{100}=1190.25 $
$ P _3=91252.5$
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Question 253 Marks
Harijyot deposited $Rs.27500$ in a deposite scheme paying $12\%$ p.a. compound interest . If the duration of the deposite is $3$ years , calculate :
The amount received by him at the end of three years.
Answer
$ C _1=\frac{27500 \times 12 \times 1}{100}=3300 $
$ P _1=27500+3300=30800 $
$ C _2=\frac{30800 \times 12 \times 1}{100}=3696 $
$ P _2=34496 $
$ C _3=\frac{34496 \times 12 \times 1}{100}=4139.52$
$ P _3=38636$
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Question 263 Marks
Ameesha loaned $Rs. 24,000$ to a friend for $2 \frac{1}{2}$ at $10 \%$ p.a. compound interest.
Calculate the interest earned by Ameesha.
Answer
$C _1=\frac{ P \times R \times T }{100}=\frac{24000 \times 1 \times 10}{100}=2400$
$ P _1=24000+2400=26400$
$C _2=\frac{26400 \times 1 \times 10}{100}=2640 $
$ P _2=26400+2640=29040 $
$C _3=\frac{29040 \times 1 \times 10}{100}=2904$
$P _4=29040+2904=31944$
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Question 273 Marks
Alisha invested $Rs.75000$ for $4$ years at $8\%$ p.a. compound interest ,
Find the amount at the end of third year.
Answer
$ C _3=\frac{ P \times R \times T }{100}=\frac{87480 \times 1 \times 8}{100}=6998.4 $
$ P _3=87480+6998.4=94478.4$
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Question 283 Marks
Alisha invested $Rs.75000$ for $4$ years at $8\%$ p.a. compound interest ,
Find the amount at the end of the second year.
Answer
$ C _1=\frac{ P \times R \times T }{100}=\frac{75000 \times 1 \times 8}{100}=6000 $
$ P _1=75000+6000=81000 $
$ C _2=\frac{ P \times R \times T }{100}=\frac{81000 \times 1 \times 8}{100}=6480 $
$ P _2=81000+6480=87480$
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Question 293 Marks
A sum of $Rs. 65000$ is invested for $3$ years at $8\%$ p.a. compound interest.
Find the sum due at the end of the second year.
Answer
$C _2=\frac{ P \times R \times T }{100}=\text { Rs } 5616$
$P _2= Rs.75816$
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Question 303 Marks
A sum of $Rs. 65000$ is invested for $3$ years at $8\%$ p.a. compound interest.
Find the sum due at the end of the first year.
Answer
$C _1=\frac{ P \times R \times T }{100} $
$=\frac{65000 \times 8 \times 1}{100}=\text { Rs. } 5200 $
$P_1=5200+65000 $
$ =\text { Rs } 70200$
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Question 313 Marks
Pradeep gave $Rs.16000$ to a friend for $1.5$ years at $15\%$ p.a. compounded semi-annually. Find the interest earned by him at the end of $1.5$ years.
Answer
$\text { Amount }= P \left(1+\frac{ r }{200}\right)^{2 t } $
$ \text { Amount }=16000\left(1+\frac{15}{200}\right)^3=\text { Rs. } 19876.75 $
$C =19876.75-16000=3876.75$
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Question 323 Marks
Shekhar had a fixed deposit of Rs 24000 for 3 years . If he received interest at 10% p.a compounded annually, find the amount received by him at the time of maturity.
Answer
Amount $= P \left(1+\frac{ r }{100}\right)^{ t }$
Amount $=24000\left(1+\frac{10}{100}\right)^3=31944$
Therefore, Shekhar received Rs . 31944 at the time of maturity.
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Question 333 Marks
Calculate the amount and the compound interest for the following:
$Rs. 40,000$ at $5 \frac{1}{4} \%$ p.a. in $1 \frac{1}{3}$ years
Answer
Here, $P=$ Rs. $40,000 ; r=5 \frac{1}{4} \%$ p.a. $=\frac{21}{4} \% ; t=1 \frac{1}{3}$ years
For the first year: $t=1$ year
$ \text { S.I. }=\frac{ P \times r \times t }{100} $
S.I. $\frac{\operatorname{Rs~} 40000 \times 21 \times 1}{100 \times 4}$
$ \text { S.I. }=\text { Rs2, } 100$
$A=P+S . I . $
$=\operatorname{Rs}(40,000+2,100)=\operatorname{Rs} .42,100=$ new principal
For the second year: $t=1 / 3$ year; $P=R s 42,100$
$ \text { S.I. }=\frac{ P \times r \times t }{100} $
$ \text { S.I. } \frac{\text { Rs } 42100 \times 21 \times 1}{100 \times 4 \times 3}$
$\text { S.I. }=\text { Rs736. } 75$
$A=P+S . I .$
$A=\operatorname{Rs}(42,100+736.75)=\operatorname{Rs}.42,836.75 $
C.I. $=$ Interest in first year +interest in second year
$ \text { C.I. }=\operatorname{Rs}(2,100+736.75)=\operatorname{Rs}.2,836.75 $
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[3 marks sum] - Mathematics STD 10 Questions - Vidyadip