SOLUTION: The rate of one plane is 80 kilometers an hour less than taht of a second. If the first plane takes 6 2/3 hours to travel the same distance that the second plane travels in 4 hours

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Question 184854: The rate of one plane is 80 kilometers an hour less than taht of a second. If the first plane takes 6 2/3 hours to travel the same distance that the second plane travels in 4 hours, find the rate of each.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The rate of one plane is 80 kilometers an hour less than that of a second.
If the first plane takes 6 2/3 hours to travel the same distance that the
second plane travels in 4 hours, find the rate of each.
:
Let r = rate of the slow plane
then
(r+80) = rate of the fast plane
:
make 6 2/3 hrs into an improper fraction, namely 20%2F3 hrs
:
Write a distance equation: Dist = time * speed
:
slow plane dist = Fast plane dist
20%2F3r = 4(r+80)
;
Mult both sides by 3 to get rid of the denominator
20r = 12(r+80)
:
20r = 12r + 960
:
20r - 12r = 960
:
8r = 960
r = 960%2F8
r = 120 km/hr is the 1st plane
and
120 + 80 = 200 km/hr is the 2nd plane
;
;
Check solutions by finding the distances
20%2F3 * 120 = 800 km
4 * 200 = 800km; confirms our solution