# At what rate of simple interest certain amount will double itself in 8 years?

(a) 12%

(b) 12 ½%

(c) 13%

(d) 15%

**Answer: (b) 12 1/2% **

**Solution:-**

Let the principal be X.

Then, Simple Interest = X

According to the question,

Rate of Interest = (100 x X)/(X x 8)

= 12.5%

Hence, the correct answer is option (b) 12 1/2%.