Questions: Question 10 (Mandatory) (1 point)
A car and a bus set out at 4 P.M. from the same point headed in the same direction. The average speed of the car is twice the average speed of the bus. In 2 h , the car is 68 mi ahead of the bus. Find the rate of the car.
68 mph
58 mph
65 mph
55 mph
Transcript text: Question 10 (Mandatory) (1 point)
A car and a bus set out at 4 P.M. from the same point headed in the same direction. The average speed of the car is twice the average speed of the bus. In 2 h , the car is 68 mi ahead of the bus. Find the rate of the car.
68 mph
58 mph
65 mph
55 mph
Solution
Solution Steps
To find the rate of the car, we need to set up an equation based on the information given. Let the speed of the bus be \( x \) mph. Then, the speed of the car is \( 2x \) mph. In 2 hours, the car travels \( 2 \times 2x = 4x \) miles, and the bus travels \( 2 \times x = 2x \) miles. The difference in distance traveled by the car and the bus is 68 miles. Therefore, we can set up the equation \( 4x - 2x = 68 \) and solve for \( x \). Once we find \( x \), we can determine the rate of the car, which is \( 2x \).
Step 1: Define Variables and Relationships
Let the speed of the bus be \( x \) mph. According to the problem, the speed of the car is twice the speed of the bus, so the speed of the car is \( 2x \) mph.
Step 2: Set Up the Equation
In 2 hours, the car travels \( 2 \times 2x = 4x \) miles, and the bus travels \( 2 \times x = 2x \) miles. The car is 68 miles ahead of the bus, so we can set up the equation:
\[
4x - 2x = 68
\]
Step 3: Solve for \( x \)
Simplify the equation:
\[
2x = 68
\]
Divide both sides by 2 to solve for \( x \):
\[
x = \frac{68}{2} = 34
\]
Step 4: Calculate the Rate of the Car
The rate of the car is \( 2x \). Substitute \( x = 34 \) into the expression for the car's speed:
\[
2x = 2 \times 34 = 68
\]
Final Answer
The rate of the car is \(\boxed{68 \text{ mph}}\).