SOLUTION: Flying with the wind a plane flew 1800 mi. in 3 hours. Against the wind, the plane required 5 hours to fly the same distance. Find the rate of the plane in calm air.
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Question 112477: Flying with the wind a plane flew 1800 mi. in 3 hours. Against the wind, the plane required 5 hours to fly the same distance. Find the rate of the plane in calm air. Answer by ptaylor(2198) (Show Source):
You can put this solution on YOUR website! Distance(d)=Rate(r) times Time(t) or d=rt; r=d/t and t=d/r
Let r=rate (speed) of plane in calm air
And let w=rate (speed) of the wind
Going with the wind:
r+w=1800/3=600 mph--------------------------eq1
Going against the wind:
r-w=1800/5=360 mph-----------------------------------eq2
Add eq1 and eq2:
2r=960 divide both sides by 2
r=480 mph--------------------------------rate (speed) of plane in calm air
Substituting into eq1:
480+w=600 subtract 480 from both sides
w=120 mph---------------- speed of wind
CK
(480+120)*3=1800
1800=1800
(480-120)*5=1800
360*5=1800
1800=1800
