a cistern is normally filled in 14 hours but takes two hours longer to fill because of a leak in its bottom . if the cistern is full , the leak will empty it in ?
"1 / 14 - 1 / x = 1 / 16 x = 112 answer : e"
inverse(subtract(divide(const_1, 14), divide(const_1, add(14, const_2))))