Question

Flying against the jet stream a jet travels 2430 miles in 3 hours. Flying with the jet stream the same jet travels 4520 miles in 4 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 the jet in still air = 970 miles per hour

,

• The speed of the jetstream = 160 miles per hour.

Step-by-step explanation:

The speed of the jet against the jet stream

`\begin{gathered} =(2430\; miles)/(3\; hours). \\ =810\text{ miles per hour} \end{gathered}`

The speed of the jet with the jet stream

`\begin{gathered} =(4520\; miles)/(4\; hours). \\ =1130\text{ miles per hour} \end{gathered}`

• Let the speed of the jet in still air = x miles per hour

,

• Let the speed of the jetstream = y miles per hour.

The speed against the jetstream = x-y

The speed with the jetstream = x-y

`\begin{gathered} x-y=810 \\ x+y=1130 \end{gathered}`

Add to eliminate y:

`\begin{gathered} 2x=1940 \\ x=(1940)/(2) \\ x=970\text{ mph} \end{gathered}`

Next, solve for y:

`\begin{gathered} x-y=810 \\ 970-y=810 \\ y=970-810 \\ y=160\text{ mph} \end{gathered}`

Thus:

• The speed of the jet in still air = 970 miles per hour

,

• The speed of the jetstream = 160 miles per hour.