The average of manny's three tests is an 84. what must he get on a 4th test to raise his averageto a 87?

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

Jackie purchased 3 bottles of water and 2 cups of coffee for the family for $7.35. ryan bought 4 bottles of water and 1 cup of coffee for his family for 7.15. how much does each bottle of water cost? how much does each cup of coffee cost?

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply