If $4,000 is deposited in a bank account paying 4% compounded quarterly, what amount will be in the account after 7 years? how much interest will be returned during the 7 years?

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

An automated water dispenser fills packets with one liter of water on average, with a standard deviation of 5 milliliter. the manual says that after a year of operation the dispenser should be tested to see if it needs recalibration. a year later a number of filled packets are set aside and measured separately. it is found that the average packet now contains about 0.995 liters. does the dispenser need calibration? explain your answer.

Tim's phone service charges $23.06 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $28.56, which equation could be used to find how many text messages, x, tim sent last month?