SOLUTION: Flying against the jetstream, a jet travels 4440km in 6 hours. Flying with the jetstream, the same jet travels 8540 km in 7 hours. What is the speed of the jet in still air, and wh

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Flying against the jetstream, a jet travels 4440km in 6 hours. Flying with the jetstream, the same jet travels 8540 km in 7 hours. What is the speed of the jet in still air, and wh      Log On


   

Question 176337: Flying against the jetstream, a jet travels 4440km in 6 hours. Flying with the jetstream, the same jet travels 8540 km in 7 hours. What is the speed of the jet in still air, and what is the speed of the jetstream?

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Rate multiplied by time equals distance.
R%2AT=D
Call the speed of the jet, R%5Bj%5D, and the speed of the jet stream, R%5Bs%5D, then,
1.%28R%5Bj%5D-R%5Bs%5D%29%286%29=4440 Jet speed minus jet stream speed
2.%28R%5Bj%5D%2BR%5Bs%5D%29%287%29=8540 Jet speed plus jet stream speed
Re-arrange eq.1 and eq. 2,
1.R%5Bj%5D-R%5Bs%5D=4440%2F6=740
2.R%5Bj%5D%2BR%5Bs%5D=8540%2F7=1220
Then add them together,
R%5Bj%5D-R%5Bs%5D%2BR%5Bj%5D%2BR%5Bs%5D=1960
2R%5Bj%5D=1960%29
R%5Bj%5D=980%29
From eq. 2,
R%5Bj%5D%2BR%5Bs%5D=1220
980%2BR%5Bs%5D=1220
R%5Bs%5D=240
The jet travels at 980 km/hr while the jet stream moves at 240 km/hr.