A sum of Rs 1600 lent at simple interest at 12.5% per annum will become double in:

 a) 3 years
 b) 7 ¼ years
 c) 8 years
 d) 9 ¼ years

SSC CHSL-2015

8 years. Solution SI = PNR/100 SI= 1600 P =1600, N = 12.5% N = (SI x 100)/ PR ==> N = 8