Given:
Speed of car A = 30 miles per hour
Speed of car B = 46 miles per hour
Let's find the time it will take the cars to be 72 miles apart.
From this situation, we have the equation that represents the situation:
46t - 30t = 72
Where t represents the time it takes for both cars to be 72 miles apart.
Let's solve for t.
46t - 30t = 72
16t = 72
Divide both sides by 16:

Therefore, it will take both cars 4.5 hours to be 72 miles apart.
Distance car B covered = 46t = 46(4.5) = 207 miles
Distance car A covered = 30t = 30(4.5) = 135 miles
The diagram that represents this situation is below:
ANSWER:
4.5 hours