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

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


   

Question 72113This question is from textbook Algebra and Trigonometry: Structure and Method
: Helped by a strong jet stream, a Los Angeles-to-Boston plane flew 10% faster than usual and made the 4400km trip in 30 min. less time than usual. At what speed does the plane usually fly? This question is from textbook Algebra and Trigonometry: Structure and Method

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Helped by a strong jet stream, a Los Angeles-to-Boston plane flew 10% faster than usual and made the 4400km trip in 30 min. less time than usual. At what speed does the plane usually fly?
:
Let s = normal speed
1.1s = the jet stream assisted speed
:
Write a time equation Time = dist/speed:
:
Jet stream time + half hr = normal time
4400%2F1.1s+%2B+.5 = 4400%2Fs
;
Multiply equation by 1.1s and you have:
4400 + 1.1s(.5) = 1.1*4400
:
4400 + .55s = 4840
:
.55s = 4840 - 4400
:
s = 440/.55
:
s = 800 km/hr normal speed
:
:
Check solution using the time:
4400/(1.1*800) + .5 = 4400/800
5 + .5 = 5.5