Question

An oil tank is being filled at a constant rate. The depth of the oil is a function of the number of minutes the tank has been filling. After 0 minutes of filling, the oil is at 3ft, and after 10 minutes of filling, the oil is at 5ft. After 90 minutes of filling, what is the depth of the oil?

a) 15 ft
b) 20 ft
c) 18 ft
d) 27 ft

Answer 1

The depth of the oil after 90 minutes of filling is 3.5 ft.

Step-by-step explanation:

To determine the depth of the oil after 90 minutes of filling, we can use a proportion. Let x represent the depth of the oil after 90 minutes. We can set up the proportion 7/x = 10/5, where 7 is the difference in depth between 3ft and x ft, and 10 is the difference in time between 0 minutes and 90 minutes. By cross-multiplying, we get 10x = 35, and by dividing both sides by 10, we find that x = 3.5 ft. Therefore, the depth of the oil after 90 minutes of filling is 3.5 ft.