8 feet = 8/3 yards
10 feet = 10/3 yards
Carpet Area = (8/3)*(10/3) = (80/9) = 8.89 square yards
Cost = ($26.35 per square yard)*(Carpet Area) + $35 installation fee
Cost = ($26.35)*(8.89) + $35
Cost = $234.22 + $35
Cost = $269.22
The carpet costs $19.22 more than his $250 budget.