A truck covers a certain distance in 12 hours at the speed of 70 kms.hr. What is the average speed of a car which travels a distance of 120 kms more than the truck in the same time ?

Options

A. 76 kms./hr.
B. 85 kms./hr.
C. 82 kms./hr.
D. None of these

Answer

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

### Step 1: Calculate the distance covered by the truck.
The distance covered by the truck can be calculated using the formula:
\[ \text{Distance} = \text{Speed} \times \text{Time} \]

Given:
- Speed of the truck = 70 km/hr
- Time taken = 12 hours

So,
\[ \text{Distance} = 70 \, \text{km/hr} \times 12 \, \text{hours} = 840 \, \text{km} \]

### Step 2: Calculate the distance traveled by the car.
The car travels a distance that is 120 km more than the truck. Therefore, the distance traveled by the car is:
\[ \text{Distance of car} = \text{Distance of truck} + 120 \, \text{km} \]
\[ \text{Distance of car} = 840 \, \text{km} + 120 \, \text{km} = 960 \, \text{km} \]

### Step 3: Calculate the average speed of the car.
The average speed of the car can be calculated using the formula:
\[ \text{Average Speed} = \frac{\text{Distance}}{\text{Time}} \]

We already know:
- Distance traveled by the car = 960 km
- Time taken = 12 hours

So,
\[ \text{Average Speed of car} = \frac{960 \, \text{km}}{12 \, \text{hours}} = 80 \, \text{km/hr} \]

### Final Answer:
The average speed of the car is **80 km/hr**.

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