SOLUTION: TAB2 NEEDS HELP... Flying against the jetstream, a jet travels 2800 km in 5 hours. Flying with the jetstream, the same jet travels 2760 in 3 hours. What is the speed of the jet

Algebra ->  Equations -> SOLUTION: TAB2 NEEDS HELP... Flying against the jetstream, a jet travels 2800 km in 5 hours. Flying with the jetstream, the same jet travels 2760 in 3 hours. What is the speed of the jet      Log On


   

Question 201109: TAB2 NEEDS HELP...
Flying against the jetstream, a jet travels 2800 km in 5 hours. Flying with the jetstream, the same jet travels 2760 in 3 hours. What is the speed of the jet in still air, and what is the speed of the jetstream?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let s = speed in still air
Let j = speed of jetstream
Flying with jetstream, plane's speed is:
s+%2B+j
Flying against jetstream, plane's speed is:
s+-+j
I can say:
2800+=+%28s+-+j%29%2A5 km
2760+=+%28s+%2B+j%29%2A3 km
----------------------
2800+=+5s+-+5j
2760+=+3s+%2B+3j
Multiply both sides of the 1st equation by 3
and both sides of the 2nd by 5
8400+=+15s+-+15j
13800+=+15s+%2B+15j
Add the equations
22200+=+30s
s+=+740 km/hr
and, since
2760+=+%28s+%2B+j%29%2A3
2760+=+%28740+%2B+j%29%2A3
2760+=+2220+%2B+3j
3j+=+540
j+=+180 km/hr