Maths 5 Mark Question

\begin{aligned}
& \text { i. Total interest }=\frac{P \times R \times T}{100} \\
& =\frac{4200 \times 7 \times 3}{100} \\
& =\text { Rs } 882 \\
& \text { Amount = Principal + interest } \\
& =4200+882 \\
& =\text { Rs } 5082
\end{aligned}\begin{aligned}
& \text { ii. Total interest }=\frac{P \times R \times T}{100} \\
& \therefore 1200=\frac{ P \times 6 \times 4}{100} \\
& \therefore \frac{1200 \times 100}{6 \times 4}= P \\
& \therefore P =\text { Rs } 5000 \\
& \text { Amount }=\text { Principal + interest } \\
& =5000+1200 \\
& =\text { Rs } 6200
\end{aligned}\begin{aligned}
& \text { iii. Total interest }=\frac{P \times R \times T}{100} \\
& \therefore 800=\frac{8000 \times 5 \times T}{100} \\
& \therefore \frac{800 \times 100}{8000 \times 5}=T \\
& \therefore T =2 \text { years } \\
& \text { Amount }=\text { Principal }+ \text { interest } \\
& =8000+800 \\
& =\text { Rs } 8800
\end{aligned}\begin{aligned}
& \text { iv. Amount = Principal + interest } \\
& \therefore 18000=\text { Principal }+6000 \\
& \therefore \text { Principal }=\text { Rs } 12000 \\
& \text { Total interest }=\frac{P \times R \times T}{100} \\
& \therefore 6000=\frac{12000 \times 5 \times T }{100} \\
& \therefore \frac{6000 \times 100}{12000 \times 5}= T \\
& \therefore T =10 \text { years }
\end{aligned}\begin{aligned}
& \text { v. } R=2 \frac{1}{2} \%=2.5 \% \\
& \therefore \text { Total interest }=\frac{P \times R \times T}{100} \\
& \therefore 2400=\frac{P \times 2.5 \times 5}{100} \\
& \therefore 2400=\frac{P \times 25 \times 5}{100 \times 10} \\
& \therefore \frac{2400 \times 10 \times 100}{25 \times 5}=P \\
& \therefore P=\text { Rs } 19200 \\
& \text { Amount }=\text { Principal + interest } \\
& =19200+2400 \\
& =\text { Rs } 21600
\end{aligned}

	Principal	Rate of interest (p.c.p.a.)	Time	Interest	Amount
i.	Rs 4200	7%	3 years	Rs 882	Rs 5082
ii.	Rs 5000	6%	4 years	Rs 1200	Rs 6200
iii.	Rs 8000	5%	2 years	Rs 800	Rs 8800
iv.	Rs 12000	5%	10 years	Rs 6000	Rs 18000
v.	Rs 19200	2.5%	5 years	Rs 2400	Rs 21600