What is the rate of simple interest for the last 5 years if the sum of ₹480 becomes ₹792 in 11 years and the rate of interest for the first 6 years is 5%?

7%

The correct answer is Option (3) → 7%

Given:
Principal $P=₹480$
Total Amount after 11 years $A=₹792$

So, total simple interest for 11 years:

$SI=792−480=₹312$

Interest for first 6 years at 5%

$SI_1 = \frac{480 \times 5 \times 6}{100} = ₹144$

Interest for last 5 years

$SI_2 = 312 - 144 = ₹168$

Rate of interest for last 5 years

$168 = \frac{480 \times R \times 5}{100}$

$R = \frac{168 \times 100}{480 \times 5} = 7\%$