Answer:
She has an initiall amount of 6 hours, so if T is the amount of time that passed since she rented the boat, the inequality that describes this system is:
0≤ T ≤ 6
This means that she can use the boat from 0 hours to 6 hours, here we are allowing the intermediate values because, of course, she can return the boat earlier than in the given time.
From this we have that the maximum time left that she has can be written as:
x + T = 6
so if T = 3h, meaning that 3 hours passed, she has:
X + 3 = 6
x = 6 - 3 = 3
3 hours left.
