Question 15 Marks
Divide $Rs. 10000$ in two parts, so that the simple interest on the first part for $4$ year at $12\%$ per annum may be equal to the simple interest on the second part for $4.5$ yr at $16\%$ per annum.
Answer
View full question & answer→Given, money$= Rs. 10000$
Now, we have divide $Rs. 10000$ in two parts such that $SI$ on first part for $4$ year at $12%$
per annum may be equal to the $SI$ on second part for $4.5$ year at $16%.$
Let first part $= 7 x$ Then, second part $= Rs (10000 - x)$
For first part, we have $P_1=$ Rs. $x, T=4$ year and $R_1=16 \%$
$\therefore \mathrm{SI}_2=\frac{\mathrm{P}_1 \times \mathrm{R}_1 \times \mathrm{T}_1}{100}=\frac{\mathrm{x} \times 12 \times 4}{100}$
For second part $(10000-\mathrm{x})$, We have
$P_2=\text { Rs. }(10000-x), T_2=4.5 \text { year and } R_2=16 \%$
$\therefore S_2=\frac{P_2 \times R_2 \times T_2}{100}=\frac{(10000-x) \times 16 \times 45}{100}$
Since, $\mathrm{SI}_1$ is equal to $\mathrm{SI}_2$.
Then, according to the question,
$\frac{\mathrm{x} \times 12 \times 4}{100}=\frac{(10000-\mathrm{x}) \times 16 \times 45}{100}$
$\Rightarrow 48 \mathrm{x}=(10000-\mathrm{x}) \times 16 \times 45$
$\Rightarrow \frac{48 \mathrm{x}}{45 \times 16}=(10000-\mathrm{x})$
$\Rightarrow \frac{48 \mathrm{x} \times 10}{45 \times 16}=10000-\mathrm{x}$
$\Rightarrow \frac{2}{3} \mathrm{x}=10000-\mathrm{x}$
$\Rightarrow \frac{2}{3} \mathrm{x}+\mathrm{x}=10000$
$\Rightarrow \frac{5 \mathrm{x}}{3}=10000$
$\Rightarrow \mathrm{x}=10000 \times \frac{3}{5}=6000$
First part $=x Rs. 6000$
Second part $=10000-x=10000-6000= Rs. 4000$
Hence, two parts of the sum are $Rs. 6000$ and $Rs. 4000.$
Now, we have divide $Rs. 10000$ in two parts such that $SI$ on first part for $4$ year at $12%$
per annum may be equal to the $SI$ on second part for $4.5$ year at $16%.$
Let first part $= 7 x$ Then, second part $= Rs (10000 - x)$
For first part, we have $P_1=$ Rs. $x, T=4$ year and $R_1=16 \%$
$\therefore \mathrm{SI}_2=\frac{\mathrm{P}_1 \times \mathrm{R}_1 \times \mathrm{T}_1}{100}=\frac{\mathrm{x} \times 12 \times 4}{100}$
For second part $(10000-\mathrm{x})$, We have
$P_2=\text { Rs. }(10000-x), T_2=4.5 \text { year and } R_2=16 \%$
$\therefore S_2=\frac{P_2 \times R_2 \times T_2}{100}=\frac{(10000-x) \times 16 \times 45}{100}$
Since, $\mathrm{SI}_1$ is equal to $\mathrm{SI}_2$.
Then, according to the question,
$\frac{\mathrm{x} \times 12 \times 4}{100}=\frac{(10000-\mathrm{x}) \times 16 \times 45}{100}$
$\Rightarrow 48 \mathrm{x}=(10000-\mathrm{x}) \times 16 \times 45$
$\Rightarrow \frac{48 \mathrm{x}}{45 \times 16}=(10000-\mathrm{x})$
$\Rightarrow \frac{48 \mathrm{x} \times 10}{45 \times 16}=10000-\mathrm{x}$
$\Rightarrow \frac{2}{3} \mathrm{x}=10000-\mathrm{x}$
$\Rightarrow \frac{2}{3} \mathrm{x}+\mathrm{x}=10000$
$\Rightarrow \frac{5 \mathrm{x}}{3}=10000$
$\Rightarrow \mathrm{x}=10000 \times \frac{3}{5}=6000$
First part $=x Rs. 6000$
Second part $=10000-x=10000-6000= Rs. 4000$
Hence, two parts of the sum are $Rs. 6000$ and $Rs. 4000.$




