to produce an annual income of rs . 1200 from a 15 % stock at 90 , the amount of stock needed is :
"solution for an income of rs . 15 , stock needed = rs . 100 . for an income of rs . 1500 , stock needed = rs . 10 / 12 x 15000 = 10,000 answer a"
subtract(const_100, 90)