SOLUTION: Helped by a strong jet stream, a Los Angeles-to-Boston plane flew 10% faster than usual and made the 4400 km trip in 30 minutes less time than usual. At what speed does the plane

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Helped by a strong jet stream, a Los Angeles-to-Boston plane flew 10% faster than usual and made the 4400 km trip in 30 minutes less time than usual. At what speed does the plane       Log On


   

Question 167940This question is from textbook
: Helped by a strong jet stream, a Los Angeles-to-Boston plane flew 10% faster than usual and made the 4400 km trip in 30 minutes less time than usual. At what speed does the plane usually fly? This question is from textbook

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let r= the plane usual speed in km/hr
Let t= the usual time to make the trip in hours
d+=+r%2At
It is given that
d+=+4400 km
4400+=+r%2At
t+=+4400%2Fr
Also given is
4400+=+%28r+%2B+.1r%29%2A%28+t+-+.5%29
4400+=+1.1r%2A%284400%2Fr+-+.5%29
4400+=+4840+-+.55r
.55r+=+440
r+=+800
and
t+=+4400%2Fr
t+=+4400%2F800
t+=+5.5
The plane usually flies at 800 km/hr
check:
4400+=+%28r+%2B+.1r%29%2A%28+t+-+.5%29
4400+=+%28800+%2B+.1%2A800%29%2A%28+5.5+-+.5%29
4400+=+880+%2A+5
4400+=+4400
OK