To determine how long it will take Sophie to visit her grandfather, we can use the formula for time:

$\text{Time} = \frac{\text{Distance}}{\text{Speed}}$

Where:

• Distance = 150 km (the distance to her grandfather's house)
• Speed = the speed at which Sophie is driving

So, depending on the speed Sophie drives, the time it will take her to reach her grandfather can be calculated by substituting different values for speed.

For example:

1. If Sophie drives at 60 km/h: $\text{Time} = \frac{150 \, \text{km}}{60 \, \text{km/h}} = 2.5 \, \text{hours}$
2. If Sophie drives at 100 km/h: $\text{Time} = \frac{150 \, \text{km}}{100 \, \text{km/h}} = 1.5 \, \text{hours}$
3. If Sophie drives at 120 km/h: $\text{Time} = \frac{150 \, \text{km}}{120 \, \text{km/h}} = 1.25 \, \text{hours} \, \text{(or 1 hour and 15 minutes)}$

If you provide a specific speed Sophie plans to drive at, I can give you the exact time it will take. Would you like to calculate it for a specific speed?

---

Further questions to explore:

1. How does changing the speed affect the total time for a trip?
2. What is the relationship between distance, speed, and time in everyday travel?
3. How do factors like road conditions or stops affect the actual time taken?
4. How can Sophie optimize her travel time when considering fuel efficiency?
5. What happens if Sophie’s speed is not constant throughout the trip?

Tip: Always consider traffic and breaks when calculating travel time. Actual times might vary based on real-world conditions!