A roast cooked at 325 degrees for four hours the internal temperature rose from 32degrees to 145 degrees what was the average rise in temperature per hour?

Rare: 11 minutes per 450g/1lb Medium: 14 minutes per 450g/1lb Well done: 16 minutes per 450g/1lb

So that's:

Rare = 11 x 4 = 44 minutes

Medium = 14 x 4 = 56 minutes

Well done = 16 x 4 = 64 minutes