Question 112477
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


Hope this helps---ptaylor