Diego is playing basketball. while running at 7 km/h toward a basketball hoop, he throws the ball at the net. the ball travels at 20 km/h. what is the speed of the ball relative to the net?

The wording is somewhat ambiguos. To avoid ambigüity, it should be stated to which frame of reference is reported the speed.of the basketball.

The options are:

1) If the speed of the ball (20 km/h) is refered to Diego, given tha the hoop is at rest, the spped of the ball relative to the net will be the speed of Diego + the speed of the ball: 7 km/h + 20 km/h = 27 km/h.

2) If the speed of the ball (20 km/h) is relative to the ground then, given that the hoop is fixed, the speed of the ball relative to the net is 20km/h.