Noelle walks from point A to point B at an average speed of 6 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 7 kilometers per hour?	Select:	A) 6.75	B) 7	C) 7.25	D) 7.5	E) 8.4
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= 2S1S2/S1+S2   7= 2*6*x/6+x   x= 8.4   8.4 is the answer
<result>E</result>
Noelle walks from point A to point B at an average speed of 6 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 7 kilometers per hour?