An electronic repair shop offers three types of service: on-site at-store and by mail. On site service costs 3 times as much as at-store service. By mail service costs $10 less than at store service. Last week the shop completed 15 services on site, 40 services at store and 5 services by mail for total sales of $2650. PART A: define variables for each service

PART B: write systems of equations for the services

PART C: Determine the cost of one on site repair service (SHOW ALL YOUR WORK)