A transporter drives his truck for the first 4 hours of his journey at a speed of 90 km/h, and the remaining distance in 6 hours at a speed of 50 km/h. What is the average speed of the truck (in km h)?

Options

A. 64
B. 70
C. 60
D. 66

Answer

To find the average speed of the truck, we will first calculate the total distance traveled during the journey and then divide it by the total time taken.

### Step 1: Calculate the distance traveled in the first part of the journey.
The truck travels for the first 4 hours at a speed of 90 km/h.

Distance = Speed × Time
Distance = 90 km/h × 4 hours = 360 km

### Step 2: Calculate the distance traveled in the second part of the journey.
The truck travels for the next 6 hours at a speed of 50 km/h.

Distance = Speed × Time
Distance = 50 km/h × 6 hours = 300 km

### Step 3: Calculate the total distance traveled.
Total Distance = Distance from first part + Distance from second part
Total Distance = 360 km + 300 km = 660 km

### Step 4: Calculate the total time taken.
Total Time = Time for first part + Time for second part
Total Time = 4 hours + 6 hours = 10 hours

### Step 5: Calculate the average speed.
Average Speed = Total Distance / Total Time
Average Speed = 660 km / 10 hours = 66 km/h

Thus, the average speed of the truck is **66 km/h**.

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