A car covers a certain distance in 3 hours at the speed of 124 kms/hr . What is the average speed of a truck which travels a distance of 120 kms less than the car in the same time ?

Options

A. 88 kms/hr.
B. 84kms/hr.
C. 78 kms/hr.
D. 73 kms/hr.

Explanation

To solve the problem step by step, we can follow these calculations:

### Step 1: Calculate the distance covered by the car.
The formula to calculate distance is:
\[ \text{Distance} = \text{Speed} \times \text{Time} \]

Given:
- Speed of the car = 124 km/h
- Time = 3 hours

So, the distance covered by the car is:
\[ \text{Distance} = 124 \, \text{km/h} \times 3 \, \text{h} = 372 \, \text{km} \]

### Step 2: Determine the distance covered by the truck.
According to the problem, the truck travels a distance that is 120 km less than the distance covered by the car.

So, the distance covered by the truck is:
\[ \text{Distance}_{\text{truck}} = 372 \, \text{km} - 120 \, \text{km} = 252 \, \text{km} \]

### Step 3: Calculate the average speed of the truck.
We know the distance covered by the truck and the time taken is the same as that of the car, which is 3 hours.

Using the formula for speed:
\[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} \]

We can calculate the average speed of the truck:
\[ \text{Speed}_{\text{truck}} = \frac{252 \, \text{km}}{3 \, \text{h}} = 84 \, \text{km/h} \]

### Final Answer:
The average speed of the truck is **84 km/h**.

---