Question 83191
time=distance/rate. seeing as the times are the same we have the following equation:
2400/(550+r)=2000/(550-r) now cross multiply:
2400(550-r)=2000(550+r)
1,320,000-2400r=1,100,000+2000r
-2400r-2000r=1,100,000-1,320,000
-4400r=-220,000
r=-220,000/-4400
r=50 mph  for the jet stream.
proof
2400/550+50)=2000/(550-50)
2400/600=2000/500
4=4