noelle walks from point a to point b at an average speed of 5 kilometers per hour . at what speed , in kilometers per hour , must noelle walk from point b to point a so that her average speed for the entire trip is 8 kilometers per hour ?
"let ' s suppose that speed while returning was xkm / h since the distance is same , we can apply the formula of avg speed avg speed = 2 s 1 s 2 / s 1 + s 2 8 = 2 * 5 * x / 5 + x x = 20 e is the answer"
divide(multiply(8, 5), subtract(multiply(const_2, 5), 8))