Question

The average flight time from Seattle (SEA) to New York (JFK) is 4.3 hours. The distance between them is 2421 miles. The average flight time going the other way, JFK to SEA is 5.5 hours. The difference is due to the jet stream. Translate this situation to a system of equations and find the average speed of the jet and the average speed of the jet stream.

Answer 1

Speed of the jet is 563.02 miles/hr

Speed of the jet stream is 122.83 miles/hr

Explanation:

The average time for going from Seattle to New York is 4.3 hours

The distance between these places is 2421 miles

The average time for going back (impaired by jet stream) is 5.5 hours

If we designate the speed of the jet = v

and the speed of the jet stream = u

then on the return trip, the relative speed of the jet = v - u

Also, recall that distance = speed x time

For the going trip, the distance covered by the jet = 4.3 x v = 2421 miles

For the return trip, the distance covered by the jet = 5.5 x (v - u) = 2421 miles

= 5.5(v - u)

these translate into the following equation written below

4.3v = 2421 ....equation 1

5.5(v - u) = 2421 ....equation 2

solving, equation 1, we'll have

4.3v = 2421

v = 2421/4.3 = 563.02 miles/hr this is the speed of the jet

substituting the value of v into equation 2, we'll have

5.5(v - u) = 2421

5.5(563.02 - u) = 2421

3096.61 - 5.5u = 2421

3096.61 - 2421 = 5.5u

675.61 = 5.5u

u = 675.61/5.5

u = 122.83 miles/hr this is the speed of the jet stream