Answer:
Malcom's family travel 15 miles per hour faster than Theo's
Explanation:
See attachment for complete question
Given
Malcom's Family:

To determine the equation of Theo's family, we refer to the attached graph.
From the graph:


First, we determine the slope, m:




Next, we determine equation for Theo's family using:



Add 50 to both sides


So, we have the following:
--- For Malcom's family
This implies that Malcom's family travel at 65 miles per hour
--- For Theo's family
This implies that Theo's family travel at 50 miles per hour
The difference between this rates is:


Which implies that Malcom's family travel 15 miles per hour faster than Theo's