You and a classmate have volunteered to contact every member of your class by phone to inform them of an upcoming event. you can complete the calls in six days if you work alone. your classmate can complete them in four days. how long will it take to complete the calls working together?

if n is the total number of calls, what expression represents the number of calls that you can make per day? what expression represents the number of calls your friend can make per day?

what is the expression for the number of days needed to make n calls if you are working together?