Question

At a pet store, Rhonda paid $55 for 8 dog bowls and 6 bones. Kelly paid $32.50 for 2 dog bowls and 9 bones. Determine the cost of one dog bowl (x) and one bone (y). Write a system of linear equations that models this situation.

Answer 1

8d + 6b = 55

2d + 9b = 32.50

Explanation:

let 'd' = # dog bowls

let 'b' + # bones

Rhonda: 8d + 6b = 55

Kelly: 2d + 9b = 32.50

we can multiply Kelly's equation by -4 to eliminate the 'd' terms:

Kelly: -4(2d + 9b) = 32.5(-4)

-8d - 36b = -130

now add the above equation to Rhonda's equation:

-8d - 36b = -130

+ 8d + 6b = 55

-30b = -75

b = 2.50

now we can use either equation and substitute 2.5 for 'b' to find 'd'

2d + 9(2.5) = 32.5

2d + 22.5 = 32.5

2d = 10

d = 5