Question

Suhail deposited a sum of 8000 at compound interest in the bank at the rate of 18% per annum

for 3 years. What interest will he get after the end of 3 years?
​

Answer 1

$Principal (P) = Rs \: 8000$

$Rate \: of \: Interest (r) = 18\%$

$Time (T) = 3 \: years$

$Conversion \: period (n) = 3$

$Let \: the \: Amount = A$

$\boxed{\pink{ A = P\Big( 1 + \frac{r}{100}\Big)^{n}}}$

$A = 8000 \Big( 1 + \frac{18}{100}\Big)^{3}$

$= 8000 \Big( \frac{100+18}{100}\Big)^{3}$

$= 8000 \Big( \frac{118}{100}\Big)^{3}$

$= 8000 \times \frac{118}{100}\times \frac{118}{100}\times \frac{118}{100}$

$= Rs \: 13144.25$

$Interest \: he \: will \:get \: after \: the \: end$

$of \: 3 \: years = A - P$

$= Rs \: 13144.25 - Rs \: 8000$

$= Rs \: 5144.25$

Therefore.,

$\red{ Interest \: he \: will \:get \: after \: the \: end}$

$\red{ of \: 3 \: years} \green { = Rs \: 5144.25 }$

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Answer 2

Given :-

• Principal (P) = Rs. 8000
• Rate of interest (R) = 18%
• Time (t) = 3years

To Find :-

• What interest will he get after the end of 3 years ?

Solution :-

As we know that,

A = P(1 + R/100)^t

↪ A = 8000(1 + 18/100)³

↪ A = 8000(118/100)³

↪ A = 8000 × 1.18 × 1.18 × 1.18

↪ A = 8000 × 1.643032

↪ A = 13144.256

↪ Amount = Rs. 13144.256.

Now, we know that,

↪ Interest = Amount - Principal

↪ Interest = 13144.256 - 8000

↪ Interest = Rs. 5144.256.

Hence,

• Interest he will get after the end of 3 years is Rs. 5144.256.