5. 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. Find the cost of each repair
service.