a) The linear function that models the amount of water after t minutes is given by:

b) It takes 92 minutes to completely fill the pond.
Item a:
- Initially, the pond contains 200 gal of water, that is, the linear function has a y-intercept of 200.
- Filled at a rate of 12 gallons per minute, thus the linear function has a slope of 12.
Then, the function is:

Item b:
It takes t minutes to fill the pond, t is found for which:

Then




It takes 92 minutes to completely fill the pond.
A similar problem is given at brainly.com/question/16302622
Subtract 1/4 x because you wanna isolate y
To find the answer, you must divide it.
189 ÷ 21 = 9
Answer: You can buy 9 packs of batteries with your $189.