PLS HELP Which number is not in the correct location?​

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?

Asap 25 pts + brainliest to right/best answer

Use set buikder notation to represent the following set: {, -2, -1, 0}