A car left Johannesburg at 14:00 for Polokwane at a speed of 64 km/h. A truck left

Johannesburg an hour later. The car and the trucktruck did not change the speeds

throughout. At 16:30, the car was 70 km ahead of the truck. Find the speed of the

truck.

Let's break down the information and solve step by step.

### Given:
- The car left Johannesburg at 14:00 at a speed of 64 km/h.
- The truck left an hour later at 15:00.
- At 16:30, the car was 70 km ahead of the truck.
- The car's and truck's speeds are constant.

### Step 1: Determine the time each vehicle traveled.
1. **Time traveled by the car by 16:30:**
   - The car left at 14:00 and we are analyzing the situation at 16:30.
   - From 14:00 to 16:30 is 2 hours 30 minutes, which is equivalent to \(2.5\) hours.

2. **Time traveled by the truck by 16:30:**
   - The truck left at 15:00 and we are analyzing the situation at 16:30.
   - From 15:00 to 16:30 is 1 hour 30 minutes, which is equivalent to \(1.5\) hours.

### Step 2: Distance traveled by the car.
Using the formula for distance:

\[
\text{Distance} = \text{Speed} \times \text{Time}
\]

The car traveled for 2.5 hours at a speed of 64 km/h:

\[
\text{Distance by car} = 64 \times 2.5 = 160 \text{ km}
\]

### Step 3: Distance traveled by the truck.
Let the speed of the truck be \( v \) km/h.

The truck traveled for 1.5 hours at speed \( v \) km/h:

\[
\text{Distance by truck} = v \times 1.5
\]

### Step 4: Use the given information about the distance gap.
At 16:30, the car was 70 km ahead of the truck:

\[
\text{Distance by car} - \text{Distance by truck} = 70
\]

Substituting the known values:

\[
160 - 1.5v = 70
\]

### Step 5: Solve for the speed of the truck.
Simplifying the equation:

\[
160 - 70 = 1.5v
\]

\[
90 = 1.5v
\]

Now, divide both sides by 1.5:

\[
v = \frac{90}{1.5} = 60 \text{ km/h}
\]

### Final Answer:
The speed of the truck is **60 km/h**.

---

Do you have any questions or need further details?

Here are 5 related questions to consider:
1. How would the solution change if the car traveled at a different speed?
2. How far would the truck be behind the car after 3 hours of travel?
3. If both vehicles started at the same time, how long would it take for the truck to catch up with the car?
4. How far apart would the vehicles be after 4 hours of travel?
5. What would the relative speed between the car and the truck be in this scenario?

**Tip:** To solve problems like these, always start by identifying the known and unknown variables, then break the problem into steps based on distance, speed, and time relationships.

A car left Johannesburg at 14:00 for Polokwane at a speed of 64 km/h. A truck left Johannesburg an hour later. The car and the truck did not change the speeds throughout. At 16:30, the car was 70 km ahead of the truck. Find the speed of the truck.

Learn how to calculate the truck's speed when a car and truck travel from Johannesburg. Using the speed-time-distance formula, this step-by-step solution explains how to solve the problem when a car is 70 km ahead of a truck at 16:30. Suitable for Grades 7-9 students.

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