renu can do a piece of work in 8 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 â € ™ s one day â € ™ s work = 1 / 8 suma â € ™ s one day â € ™ s work = 1 / 4 - 1 / 8 = 1 / 8 suma can do it alone in 8 days . answer : a"
inverse(subtract(divide(const_1, 4), divide(const_1, 8)))