Question

What is the average speed of the car if it covers 200 km in 5 hours (in km/h)?

• A. 50
• B. 60
• C. 35
• D. 40

Hint:

Average speed is always Total Distance $\div$ Total Time --- never the arithmetic mean of individual speeds unless the time durations are equal. If a car covers the first half in time $t_1$ and second half in time $t_2$, the average speed is $\dfrac{d}{t_1+t_2}$, not $\dfrac{v_1+v_2}{2}$. Always go back to the basic formula.

Answer 1

The Correct Option is D

Concept:
The fundamental formula for average speed is:
This formula applies when the total distance and total time are both known, regardless of whether the speed was constant or variable during the journey. Average speed is a scalar quantity and is always expressed in units of distance per unit time (e.g.
km/h, m/s).

Step 1: Identify the given values.

• Total distance covered \(= 200\) km.

• Total time taken \(= 5\) hours.

Step 2: Apply the average speed formula.


Step 3: Perform the division.


Step 4: Check the other options.

• (A) 50 km/h: Would require covering 250 km in 5 hours.

• (B) 60 km/h: Would require covering 300 km in 5 hours.

• (C) 35 km/h: Would require covering 175 km in 5 hours.

• (D) 40 km/h: $40 \times 5 = 200$ km.