A pilot flew to Montreal and back . The average speed going was 320 mph , and the average speed returning was 480 mph. Find the distance to Montreal if the total flying time was 5 hours.

1 answer

let the distance be d km
time on first trip = d/320
time on return trip = d/480

d/320 + d/480 = 5
the LCD is 960
3d/960 + 2d/960 = 5
5d/960 = 5
d/960 = 1
d = 960

(in Montreal they would use km and km/h, not miles and mph)