Karabo and John are at the same rest stop alongside a highway. Karabo started driving along the highway at a constant speed of \( 80 \mathrm{~km} / \mathrm{h} \). An hour later, John started driving along the same highway in the same direction as Karabo at the constant speed of \( 100 \mathrm{~km} / \mathrm{h} \). How long will it take John to catch up with Karabo?

To determine how long it will take John to catch up with Karabo, we can set up a simple equation based on their speeds and the time they have been driving. 1. **Karabo's Distance**: Since he drives for 1 hour longer than John at 80 km/h, the distance Karabo has covered when John starts is: \[ \text{Distance}_{Karabo} = \text{Speed}_{Karabo} \times \text{Time}_{Karabo} = 80 \text{ km/h} \times 1 \text{ h} = 80 \text{ km} \] 2. **John's Speed Advantage**: John starts driving after 1 hour and travels at 100 km/h. The difference in their speeds is: \[ \text{Speed Difference} = \text{Speed}_{John} - \text{Speed}_{Karabo} = 100 \text{ km/h} - 80 \text{ km/h} = 20 \text{ km/h} \] 3. **Catch-Up Time**: John needs to make up the 80 km distance at a speed of 20 km/h: \[ \text{Time}_{catch-up} = \frac{\text{Distance}}{\text{Speed Difference}} = \frac{80 \text{ km}}{20 \text{ km/h}} = 4 \text{ hours} \] Thus, John will take 4 hours to catch up with Karabo.