Let the rate of the first mechanic be r₁ dollars per hour and the rate of the second mechanic be r₂ dollars per hour.
The total cost of the two mechanics is 10r₁+15r₂=$2800.
Also r₁+r₂=$225, so r₂=225-r₁ which can be substituted into the other equation:
r₁=575/5=$115 per hour, so r₂=225-115=$110 per hour.
So the hourly rates are $115 and $110.