Yes what do you need help with?
I = PRT.....rearrange.....P = I / RT
P = 51 / (0.0425* 2).....I used 2 because 24 months = 2 yrs
P = 51 / 0.085
P = 600 <===
Answer:
7
Step-by-step explanation:
In general, the point of an inverse function is to show you the value that gives a particular function value. That is, ...

0.5 gallons every day
1 weeks = 7 days
0.5 gallons x 7 days = 3.5 gallons every week
1 gallon = 16 cups
3 1/2 gallons = 3 1/2 x 16 = 56 cups
Katrina drinks 56 cups of water every week