Question

2. What was the original amount deposited on an account with a total amount of $80 in the account after 8 years with a 2% Interest rate?

Answer 1

Given:

Total amount = $80

Number of years, n = 8

Rate of interest, r = 2%

The objective is to find the principal amount (p) deposited in the account.

The general formula to find the interest is,

$A=\frac{p\cdot n\cdot r}{100}$

Since,

Total amount=Principal amount+Interest amount

Total=p+A

80=p+A

A=80-p

Let's substitute the values in the general formula.

$\begin{gathered} A=\frac{p\cdot n\cdot r}{100} \\ 80-p=\frac{P\cdot8\cdot2}{100} \\ 80-p=\frac{16p}{100} \\ 100(80-p)=16p \\ 8000-100p=16p \\ 8000=16p+100p \\ 116p=8000 \\ p=\frac{8000}{116} \\ p=68.965 \\ p\cong69 \end{gathered}$

Hence, the original amount deposited on the account is $69.