SOLUTION: A plane can fly 600 miles in the same time it takes a car to go 240 miles. If the car travels 90 mph slower than the plane, find the speed of the plane

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A plane can fly 600 miles in the same time it takes a car to go 240 miles. If the car travels 90 mph slower than the plane, find the speed of the plane      Log On


   

Question 721115: A plane can fly 600 miles in the same time it takes a car to go 240 miles. If the car travels 90 mph slower than the plane, find the speed of the plane
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = the time for both
Let +p+ = the speed of the plane
+p+-+90+ = the speed of the car
Equation for car:
(1) +240+=+%28+p-90+%29%2At+
Equation for plane:
(2) +600+=+p%2At+
----------------
(2) +t+=+600%2Fp+
and
(1) +240+=+%28+p+-+90+%29%2A%28+600%2Fp%29+
(1) +240+=+600+-+54000%2Fp+
(1) +240p+=+600p+-+54000+
(1) +360p+=+54000+
(1) +p+=+150+
The plane's speed is 150 mi/hr
check:
(2) +600+=+p%2At+
(2) +t+=+600%2F150+
(2) +t+=+4+ hrs
and
(1) +240+=+%28+p-90+%29%2At+
(1) +240+=+%28+150-90+%29%2At+
(1) +240+=+60t+
(1) +t+=+4+ hrs
OK