Answer:
it will take the cars t = 0.125 h for them to have a distance of 15 km between them.
Explanation:
at the instant the cars are 15 km apart they gonna have to move:
75×t and 45×t respectively
where t is the time it will take them to be move until they 15 km apart,then to find the time:
75×t + 45×t = 15
120×t = 15
t = 0.125 h
Therefore, it will take the cars 0.125 hours for them to end up being 15 km apart.