**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