kathleen can paint a room in 2 hours , and anthony can paint an identical room in 5 hours . how many hours would it take kathleen and anthony to paint both rooms if they work together at their respective rates ?
"( 1 / 2 + 1 / 5 ) t = 2 t = 20 / 7 answer : a"
multiply(divide(const_1, add(divide(const_1, 2), divide(const_1, 5))), 2)