a can finish a piece of work in 4 days . b can do it in 12 days . they work together for two days and then a goes away . in how many days will b finish the work ?
"2 / 4 + ( 2 + x ) / 12 = 1 = > x = 4 days answer : a"
divide(subtract(const_1, add(multiply(divide(const_1, 4), const_2), multiply(divide(const_1, 12), const_2))), divide(const_1, 12))