Please help. pleasee

Aretha wanted to gather data about the cost of local bowling leagues in her area. she plotted the data and determined that the average bowling league costs consist of a one-time registration fee and a monthly fee modeled by the equation y = 15x + 20. identify and interpret the y-intercept in this model. the y-intercept is 20. this is the cost per month. the y-intercept is 20. this is the cost of registration. the y-intercept is 15. this is the cost of registration. the y-intercept is 15. this is the cost per month.

Hi i’m not sure how to do question 20 if u could explain how to do it that’d b great

Three friends are comparing the prices of various packages of golf balls at a sporting goods store. hector finds a package of 6 golf balls that costs $4.50.