To solve for $t$, the time in hours that Sam travels on the highway, we need to focus on the portion of his journey on the highway, as the problem asks for the time to reach a farm that is 22 kilometers away from his house.

Given:

• Sam traveled 7.5 kilometers from his house to reach the highway.
• The total distance to the farm from Sam's house is 22 kilometers.
• The remaining distance Sam needs to travel on the highway to reach the farm is $22 - 7.5$ kilometers.
• The average speed on the highway is 55 kilometers per hour.

The distance Sam travels on the highway is: $\text{Distance on the highway} = 22 - 7.5 = 14.5 \text{ kilometers}$

The relationship between distance, speed, and time is given by: $\text{Distance} = \text{Speed} \times \text{Time}$

Plugging in the known values: $14.5 = 55 \times t$

To solve for $t$, we divide both sides by 55: $t = \frac{14.5}{55}$

So, the equation to solve for $t$ is: $\boxed{t = \frac{14.5}{55}}$

This equation represents the time in hours that Sam spends traveling on the highway to reach the farm.

Would you like more details on how to solve this equation, or do you have any other questions?

Here are 5 related questions for further practice:

1. If Sam had traveled at 60 kilometers per hour instead of 55, how long would it take him to reach the farm?
2. What is the total time Sam spent traveling from his house to the farm?
3. How far would Sam have traveled if he continued on the highway for 30 minutes?
4. What is the total distance covered by Sam on his entire journey?
5. How would the equation change if the farm were 30 kilometers away from Sam’s house?

Tip: Remember that speed, distance, and time are related through the formula $\text{Distance} = \text{Speed} \times \text{Time}$. This is a fundamental concept that helps in solving many motion problems.