Day and night on my mind please don't kill the vibe

Carter drank 15.75 gallons of water in 4 weeks. he drank the same amount of water each day.a. estimate how many gallons he drank in one day.b. estimate how many gallons he drank in one week.c. about how many days altogether will it take him to drink 20 gallons?

What is the solution to the equation in the & show work i’m very

What can you determine about the solutions of this system