Problem: if it takes a tub 5 minutes to drain 5 / 7 of its content , how much more time will it take for the tub to be empty ?
Rationale: "if 5 / 7 of tub ' s content is drained 2 / 7 th of tub still needs to be drained . if it takes 5 minutes to drain 5 / 7 th of tub it takes 5 * ( 7 / 5 ) minutes to drain the entire tub and 5 * ( 7 / 5 ) * ( 2 / 7 ) min to drain 2 / 7 th of the tub which is 2 minutes so answer is d"
annotated_formula: add(subtract(const_1, divide(5, 7)), divide(5, 7))