magical cook wrote:Hi Can anyone help with this? thanks

It is a good question from remote to answer. Seems something wrong somewhere, I don't know...

Average speed in the first 45 minutes = distance traveled in the first 45 minutes/45 minutes

From the graph

Distance traveled in the first 45 minutes = 24 - 12 = 12 kilometer. Time taken = 45 minutes = ¾ hour.

Average speed in the first 45 minutes = 12/ (¾) kilometer per hour = 16 kilometer per hour.

He completes the remaining 12 kilometer in the last 15 minutes, hence the average speed in the last 15 minutes = 12/ (¼) kilometer per hour = 48 kilometer per hour, which is 48 - 16 = [spoiler]32[/spoiler] kilometer per hour more than his average speed in the first 45 minutes.

Hence the answer must be [spoiler]32[/spoiler], none of the choices.