renu can do a piece of work in 6 days , but with the help of her friend suma , she can do it in 4 days . in what time suma can do it alone ?
"renu ’ s one day ’ s work = 1 / 6 suma ’ s one day ’ s work = 1 / 4 - 1 / 6 = 1 / 12 suma can do it alone in 12 days . answer : b"
inverse(subtract(divide(const_1, 4), divide(const_1, 6)))