a lent rs . 4000 to b for 2 years and rs . 2000 to c for 4 years on simple interest at the same rate of interest and received rs . 2200 in all from both of them as interest . the rate of interest per annum is :
explanation : let the rate of interest per annum be r % simple interest for rs . 4000 for 2 years at r % + simple interest for rs . 2000 for 4 years at r % = 2200 ( 4000 × r × 2 ) / 100 + ( 2000 × r × 4 ) / 100 = 2200 80 r + 80 r = 2200 160 r = 2200 16 r = 220 4 r = 55 r = 55 / 4 = 13.75 % answer : option d
multiply(divide(2200, add(multiply(4000, 2), multiply(2000, 4))), const_100)