Question

Flying against the wind, a jet travels 4400mi in 8 hours. Flying with the wind, the same jet travels 5820mi in 6 hours. What is the rate of the jet in still air and what is the rate of the wind?

Answer 1

Let J = rate of jet in still airLet W = rate of wind Distance formula:  d = rt   /   r = d/t Flying against the wind the jet flies at a rate of  J - W = 1860 miles/3 hours = 620 miles per hourFlying with the wind the jet flies at a rate of J+W = 9180 miles/9 hours = 1020 miles per hour The average of these 2 rate is the speed of the jet in still air J = (620+1020)/2 = 820 miles per hour J - W = 620  

820 - W = 620
W = 820 - 620 = 200 miles per hour The jet in still air flies at a rate of 820 mph(miles per hour)The wind speed is 200 mph(miles per hour)