Question

There is $80\%$ increase in an amount in 8 years at simple interest. What will be the compound interest of Rs. 14,000 after 3 years at the same rate?

• A. Rs.3794
• B. Rs.3714
• C. Rs.4612
• D. Rs.4634

Answer 1

The correct option is D

Rs.4634

Let P = Rs.100

Simple Interest = Rs. 80 $(\because 80\%$ increase is due to the simple interest )

Rate of interest =$\left(\frac{100\times SI}{PT}\right)=\frac{100\times 80}{100\times 8}=10\%perannum$

Now let's find out the compound interest of Rs. 14000 after 3 years at $10\%$

P = Rs. 14000

T= 3 years

R = $10\%$

Amount after 3 years = P${\left(\frac{1+R}{100}\right)}^T$

= 14000${\left(\frac{1+10}{100}\right)}^3$

=14000${\left(110100\right)}^3$

= 14000${\left(\frac{11}{10}\right)}^3$

= $14\times {11}^3$= Rs.18634

Compound Interest = Rs.18634 - Rs.14000 = Rs. 4634