Question

Water tank is being filled with water. Before water is pumped in, the water level in the tank is 12 inches high. After 20 minutes, the water level is 54 inches high.

If t represents the time in minutes and h represents the water level, which of the following equations can be used to model this situation?
A. H = 42 + 12t
B. H = 2.1t - 12
C. H = 12t + 2.1
D. H = 2.1t + 12

Answer 1

D. H = 2.1t + 12

Explanation:

Let us assume the t be the time in minutes

And h be the water level

Now before reaching to the equation that need to be used

before this, determine the inches per minute i.e.

= 54 inches - 12 inches

= 42 inches in 20 minutes.

Now for per minute, it would be

= 42 inches ÷ 20 minutes

= 2.1 inches per minute

After this, multiply the inches per minute with the minutes t and add the sale to the beginning value i.e. 12

So the equation is

H = 2.1t + 12

hence, the last option is correct