a and b can do a piece of work in 12 days and 16 days respectively . both work for 3 days and then a goes away . find how long will b take to complete the remaining work ?
"3 / 12 + ( 3 + x ) / 16 = 1 x = 9 days answer : d"
divide(subtract(3, add(divide(3, 16), divide(3, 12))), divide(3, 16))