Question

A group of nine friends go to a baseball game. The group buys 6 hotdogs and 3 hamburgers for a total of $27.75. A hamburger costs $1.75 more than a hot dog. What is the cost of a hamburger?

Answer 1

let x be cost of a hotdog

let y be cost of hamburger

so,

5x + 4y = 17.75 eq. 1

4x + 5y = 18.25 eq. 2

manipulate eq. 1 so solve for x:

5x = 17.75 - 4y

x = 17.75/5 - (4/5)y

x = 3.55 - (4/5)y eq. 3

substitute eq. 3 to eq. 2:

4(3.55 - (4/5)y) + 5y = 18.25

14.2 - (16/5)y + 5y = 18.25

14.2 + (9/5)y = 18.25

(9/5)y = 18.25 - 14.2

4.05= (9/5)y

y = 2.25

x = 3.55 - (4/5)(2.25)

x = 1.75

hotdog costs $1.75

hamburger costs $2.25

Explanation: