a can do a work in 20 days , b in 30 days . a alone start the work after 10 days he left work . in how many days b can finish the work ?
"10 days work of a = 10 / 20 = 1 / 2 remaining work = 1 - 1 / 2 = 1 / 2 b can finish 1 / 2 work = 30 * 1 / 2 = 15 days answer is e"
divide(subtract(const_1, multiply(10, divide(const_1, 20))), divide(const_1, 30))