Question

Flying against the jetstream, a jet travels 7380 miles in 9 hours. Flying with the jetstream, the same jet travels 9920 miles in 8 hours. What is the rate of the jet in still air and what is the rate of the jetstream?

Answer 1

Answer:

The rate of the jet in still air = 1030 miles per hour

And 210 miles per hour is the rate of the stream.

Step-by-step explanation:

Let the speed of the jet in still air be $x$ miles per hour.

And,the speed of the jetstream be $y$ miles per hour.

Key:So when it is moving against the stream speed will be $(x-y)$ and when it is moving with the stream, speed will be $(x+y)$

And we know that.

Distance=Speed multiplied with time.

Arranging the equation.

$9920=8 \times (x+y)$...equation 1

$7380=9 \times (x-y)$...equation 2

Working with the equation by using elimination method.

Dividing equation 1 with 8 and equation 2 with 9.We will have

1240=$(x+y)$...eqn 3

820=$(x-y)$...eqn 4

Now adding both the equation will decimate y.

1240+820=2$x$

2060=2$x$

Dividing with 2 both sides.

1030=$x$

By plugging the value of $x$ we can find y in equation 3.

1240=1030 + $y$

Subtracting 1030 from both sides.

1240-1030=$y$

$y$ =210 miles per hour

So the rate of the jet in still air = 1030 miles per hour

And 210 miles per hour is the rate of the jet stream.