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 [tex]x[/tex] miles per hour.
And,the speed of the jetstream be [tex]y[/tex] miles per hour.
Key:So when it is moving against the stream speed will be [tex](x-y)[/tex] and when it is moving with the stream, speed will be [tex](x+y)[/tex]
And we know that.
Distance=Speed multiplied with time.
Arranging the equation.
[tex]9920=8 \times (x+y)[/tex]...equation 1
[tex] 7380=9 \times (x-y)[/tex]...equation 2
Working with the equation by using elimination method.
Dividing equation 1 with 8 and equation 2 with 9.We will have
1240=[tex](x+y)[/tex]...eqn 3
820=[tex](x-y)[/tex]...eqn 4
Now adding both the equation will decimate y.
1240+820=2[tex]x[/tex]
2060=2[tex]x[/tex]
Dividing with 2 both sides.
1030=[tex]x[/tex]
By plugging the value of [tex]x[/tex] we can find y in equation 3.
1240=1030 + [tex]y[/tex]
Subtracting 1030 from both sides.
1240-1030=[tex]y[/tex]
[tex]y[/tex] =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.
