Could somebody PLZ help me. Correct answers get

Kelly is a salesperson at a shoe store, where she must sell a pre-set number of pairs of shoes each month. at the end of each work day the number of pairs of shoes that she has left to sell that month is given by the equation s=300-15x , where s is the number of pair of shoes kelly still needs to sell and x is the number of days she has worked that month. what is the meaning of the number 300 in this equation

A10 inch cookie cake is divided into 8 slices. what is the area of 3 slices

Jared had 3/7 of the minutes on a family phone plan remaining for the month. the plan is shared by 2 people. if divided equally what portion of the minutes remaining on the phone plan would be avalible for each person