144k views
1 vote
A car and a motorcycle leave at noon from the same location, heading in the same direction. The average speed of the car is 30 mph slower than twice the speed of the motorcycle. In two hours, the car is 20 miles ahead of the motorcycle. Find the speed of both the car and the motorcycle, in miles per hour.

User Ddemidov
by
8.7k points

2 Answers

1 vote
The car is going at a speed of 50 mph and the motorcycle is going at a speed of 40 mph.
40*2=80
80-30=50
50-40=10
10*2 hours= 20
I hope I helped!
User War Gravy
by
7.9k points
0 votes

Answer:

Motorcycle : 40 miles per hour

Car: 50 miles per hour

Explanation:

Hi, we have to write a system of equations.

The average speed of the car is 30 mph slower than twice the speed of the motorcycle.

  • C = 2 M -30 (first equation)

Where

C = speed rate of the car

M = speed rate of the motorcycle

since distance = speed x time

In two hours(time), the car is 20 miles(distance) ahead of the motorcycle.

Since the car is ahead of the motorcycle , the speed is the difference of both.(C-M)

  • 20 = (C-M) 2 (second equation)

Replacing the value of C by 2 M -30 , in the second equation:

20 = [(2M-30)-M ]2

20 = [M-30]2

20 = 2M-30(2)

20= 2M -60

20+60 =2M

80 = 2M

80/2 =M

M =40 km per hour

Replacing M in the first equation:

C = 2 (40)-30 = 80-30

C = 50 km per hour

User Insign
by
7.4k points