Question

A plane flew from Calgary to Toronto, a flying distance of 2720 km. On the return journey, due to a strong head wind, the average flying speed was 80km/hr slower than on the outward journey. The time taken for the return journey was 40 minutes more than for the outward journey. Calculate the time taken for the journey from Calgary to Toronto. Calculate the time time taken for the whole trip. Calculate the average speed of the plane from Toronto to Calgary.

Answer 1

40 min = .667 hour
ground plane speed in still air = v
speed against the wind = (v-80)
Tct = 2720 / v
Ttc = 2720 / (v-80)
Ttc - Tct = .667 hour = 2720 / (v-80) - 2720 /v
.667 (v-80)(v) = 2720 [ v -v+80 ]
.667 v^2 - 53.3 v - 217600 = 0
v = 613 km/h or -533 km/h, use the positive root, 613 km/h