Question

Flying against the wind, a jet travels 2480 miles in 4 hours. Flying with the wind, the same jet travels 7040 miles in 8 hours. What is the rate of the jet in still air and what is the rate of the wind?

Answer 1

The speed of jet in still air is 750 miles per hour and speed of wind is 130 miles per hour.

Explanation:

Given that:

Distance traveled by jet against the wind = 2480 miles in 4 hours

Combined speed =
`(Distance)/(Time)` =
`(2480)/(4)`

Combined speed = 620 miles per hour

Distance traveled with wind = 7040 miles in 8 hours

Combined speed =
`(7040)/(8)`

Combined speed = 880

Let,

Speed of jet = x

Speed of wind = y

When jet travels against the wind, the speed will be subtracted

x-y=620 Eqn 1

When jet travels with the wind, the speed will be added

x+y=880 Eqn 2

Adding Eqn 1 and 2

(x-y)+(x+y)=620+880

x-y+x+y=1500

2x=1500

Dividing both sides by 2

`(2x)/(2)=(1500)/(2)\\x=750`

Putting x=750 in Eqn 2

750+y=880

y=880-750

y=130

Hence,

The speed of jet in still air is 750 miles per hour and speed of wind is 130 miles per hour.