3 2/5= 17/5,
17/5÷7/8=136/35,
17/5(8/7)=136/35,
136÷35=3.89,
3 2/5= 17/5,
17/5÷7/8=136/35,
17/5(8/7)=136/35,
136÷35=3.89,
so the answer is 3.89 mph, or 3 89/100 mph.
I am sorry if I got it wrong, I tried. If I left out something, or you don't understand something, tell me in the comments.
