Question

A jet travels 6588 miles against a jetstream in 9 hours and 7938 miles with the jetstream in the same amount of time. What is the rate of the jet in still air and what is the rate of the jetstream?

Answer 1

807mph is the rate of the jet, and 75mph is the jetstream.

Explanation:

We need to start from the formula of speed: V=d/t

We have two travels, with and against the jetstream, both done in the same time (9hr). We can arrange a equation sytem with this information;

V - X = 6588miles/9hr (against the jetstream, X).

V + X = 7938miles/9hr (with the jetstream, X).

Clear V from the 1st equation:

V = (6588/9) + X

V = 732 + X

Now, replace it into the 2nd equation:

(732+X) + X = 7938/9

2X + 732 = 882

2X = 882 - 732

X = 150/2

X = 75mph is the jetstream.

Now we have, the jetstream, replace it into any of the equation to find V:

V - 75mph = 6588mi/9h

V = 732mph + 75mph

V = 807mph is the rate of the jet.