What is the correct answer?

4

A. 34 years

B. 37 years

C. 45 years

D. 47 years

P(1+R/100)^{15}=2P

(1+R/100)^{15}=2P/P=2

LET P(1+R/100)^{n}=8P

(1+R/100)^{n}=8=2^{3}={(1+R/100)^{15}}^{3}[USING (I)]

(1+R/100)^{N}=(1+R/100)^{45}

n=45.

Thus, the required time=45 years.