Question

Flying against the jetstream a jet travels 8100 miles in nine hours flying with the jet stream the same jet travels 6100 miles in five hours what is the rate of the jet in still air and what is the rate of the jet stream

Answer 1

The speed of jet in still air is 1060 miles per hour And

The speed of jet stream is 160 miles per hour .

Explanation:

Given as ;

The Distance of jet against jet stream is 8100 miles

The Time taken by jet against jet stream is 9 hours

The Distance of jet with jet stream is 6100 miles

The Time taken by jet with jet stream is 5 hours

Let the speed of jet in still air = x mph

And The speed of jet stream = y mph

Now, Speed =
`(Distance)/(Time)`

So, According to question

The speed of jet against jet stream =
`(Distance of jet against jet stream)/(Time taken by jet against jet stream)`

I.e x - y =
`(8100)/(9)`

Or , x - y = 900 mph .....A

Again ,

The speed of jet with jet stream =
`(Distance of jet with jet stream)/(Time taken by jet with jet stream)`

I.e x + y =
`(6100)/(5)`

Or , x + y = 1220 mph .......B

Solve equation A and B

so, ( x + y ) + ( x - y ) = 1220 + 900

or, 2 x = 2120 mph

∴ x =
`(2120)/(2)` = 1060 miles per hour

And From eq A

x - y = 900 mph

y = x - 900

Or, y = 1060 - 900 = 160 miles per hour

Hence The speed of jet in still air is 1060 miles per hour And The speed of jet stream is 160 miles per hour . Answer