A sum of money invested at x% simple interest per annum amounts to ₹2,368 in 6 years and to ₹3,008 in 11 years. Find the value of x.

Correct option is A

Given:

Amount after 6 years = ₹2,368

Amount after 11 years = ₹3,008

Formula Used

​$$\text{Simple Interest (SI)} = \frac{P \times R \times T}{100}$$​​

Where:

P = Principal

R= Annual rate of interest 

T = Time in years​

Solution:

Time difference = 11 - 6 = 5 years
Interest for 5 years = 3008 - 2368 = ₹640
Simple Interest per year =$$\frac{₹640 } 5$$​= ₹128

Now, Principal = Amount after 6 years - SI for 6 years
SI for 6 years = 128 × 6 = ₹768
Principal = 2368 - 768 = ₹1600

R = $$\frac{128 \times 100}{1600 \times 1} = 8\%$$​