Multiply the total mile trip by the percentage in decimal form (divided by 100)
85% / 100 = 0.85
For the 900 mile trip:
900 x 0.85 = 765
Riley flew 765 miles out of a total 900-mile trip.
So, the first 2 options are False
For a 1200 mile trip:
1200 x 0.85 = 1020
Riley flew 1020 miles out of total 1200 mile trip.