Question 302987
A plane can fly 420 miles in the same time as it takes a car to go 120 miles. If the car travels 100 mph slower than the plane, find the speed of the plane.

so what is the speed of the plane ?

thank you :)

Letthe rate of the plane be x

distance traveled by plane = 420 miles

time taken by plane = 420/x

distance traveled by car =120 miles

rate of car = x-120

time taken by car = 120 / x-100

the time taken by both are same

420/x = 120/ x-100

420(x-100)=120x

420x-42000 = 120x

420x-120x=42000

300x= 42000

x=42000/300

x=140 mph  the speed of the plane


Ananth