ASAP
He pays $15 per month and $0.20 per minute for local air time. Calvin signed up for another plan. He pays $25 per month and $0.10 per minute.
a) Write an equation representing Korey's cellular phone service.
b) Write an equation representing Calvin's cellular phone service.
c) Solve a system of equations to calculate when Cory's and Calvin's costs are the same. After how many minutes will this occur? write your answer in the form (x,y)