So we know Miguel has 20$ so from there we subtract the prices of the movies ticket, snacks, and the bus fares.
20 - 6.25 = 13.75
13.75 - 3.70 = 10.05
Since the bus fare is each way (to and back) we multiply 1.25 x 2
1.25 x 2 = 1.50
10.05 - 1.50 = 8.55
He has $8.55 left