Answer: Cheddar = 3 lbs, Swiss = 2.5
Explanation:
 Quantity Cost
Cheddar x 7.95 
Swiss y 9.50
Total: 5.5 47.60 
Qty: x + y = 5.5 ⇒ -7.95(x + y = 5.5) ⇒ -7.95x -7.95y = -43.725 
Cost: 7.95(x) + 9.50(y) = 47.60 
Use elimination to solve.
 -7.95x - 7.95y = -43.725 
 7.95(x) + 9.50(y) = 47.60
 1.55y = 3.875
  ÷ 1.55  ÷ 1.55  
 y = 2.5
Qty: x + y = 5.5
 x + 2.5 = 5.5
  -2.5  -2.5
 x = 3.0