Question

Flying against the jetstream, a jet travels 3950 miles in 5 hours. Flying with the jetstream, the same jet travels 10,170 miles in 9 hours. What is the rate of thejet in still air and what is the rate of the jetstream?

Answer 1

Velocity of that jet flying against the jetstream is:

`V_1=(3950)/(5)=790\text{ miles/hour}`

And the velocity of that jet flying with the jetstream is:

`V_2=(10170)/(9)=1130\text{ miles/hour}`

Let the velocity of that jet in still air be x miles per hour and the velocity of jetstream be y miles per hour, so:

`x-y=790`

and

`x+y=1130`

Adding the two equations we have:

`(x-y)+(x+y)=790+1130`
`x-y+x+y=1920`
`2x=1920`
`x=(1920)/(2)`
`x=960`

the velocity of that jet in still air is 960 miles per hour.

And the rate of the jetstream "y" is (replacing x in the first equation):

`x-y=790`
`960-y=790`
`y=960-790`
`y=170`

170 miles per hour