Problem: a pump can fill a tank with water in 3 hours . because of a leak , it took 3 1 / 3 hours to fill the tank . the leak can drain all the water of the tank in ?
Rationale: "work done by the tank in 1 hour = ( 1 / 3 - 3 1 / 3 ) = 1 / 30 leak will empty the tank in 30 hrs . answer : c"
annotated_formula: inverse(subtract(divide(1, 3), inverse(divide(add(multiply(3, 3), 1), 3))))