Question

Chapter :- Simple InterestCalculate the sum which amounts to Rs. 808 in $2 \frac{1}{2} \: years$at$10 \frac{1}{2} \% \: p.a.$

Answer 1

To solve this question using simple interest, use the formula below.

$A=P(1+rt)$

Where:

A = Final amount.

P = Initia principal.

r = rate.

t = time.

In this exercise,

A = 808

P = to be found

r = 0.105

t = 2.5

Then, substituting the values:

$\begin{gathered} 808=P\cdot(1+0.105\cdot2.5) \\ 808=1.2625P \end{gathered}$

Dividing both sides by 1.2625:

$\begin{gathered} \frac{808}{1.2625}=\frac{1.2625}{1.2625}P \\ 640=P \end{gathered}$

Answer: the sum that amounts to 808 is 640.