Question

A sum of Rs. 12,000 deposited at compound interest doubles after 5 years. After 20 years it will become

• A. Rs. 1,20,000
• B. Rs. 1,92,000
• C. Rs. 1,24,000
• D. Rs. 96,000

Answer 1

The correct option is B Rs. 1,92,000

According to the question
After 5 year
$12000\times (1+\frac{R}{100}{)}^5=24000$
$(1+\frac{R}{100}{)}^5=2$
After 10 year
$\left(\right((1+\frac{R}{100}{)}^5{)}^4)=2^4$
$(1+\frac{R}{100}{)}^{20}=16$
$P(1+\frac{R}{100}{)}^{20}=16\times P=16\times 12000=192000$