Flying into the wind, a helicopter takes 15 minutes to travel 15 kilometers. the return flight takes 12 minutes

helicopter
wind-speed

#1

flying into the wind, a helicopter takes 15 minutes to travel 15 kilometers. the return flight takes 12 minutes. the wind speed remains constant during the trip.

a) find the helicopters average speed(in kph) for each leg of the trip

b)write a system of linear equations that represents the situation.

c) what is the helicopters average speed in still air? what is the speed of the wind?

Answer:

a) upwind … 15 km / 15 min = 1 km/min = 60 kph
… downwind … 15km / 12 min = 5/4 km/min = 75 kph

b) d = r t
… 15 km = (h - w) * 1/4 … 60 = h - w
… 15 km = (h + w) * 1/5 … 75 = h + w

c) adding the equations from b) … 135 = 2 h , 67.5 = h
… substituting … 75 = 67.5 + w … 7.5 = w