At a concession stand three hot and 4 hamburgers cost 13.50; 4 hot dogs and 3 numbers cost 12.75. Find the cost one hot dog and the cost of one hamburger

Answer 1

x = the cost of hot dog

y = the cost of hamburger

3 x + 4 y = 13.5

4 x + 3 y = 12.75

3 x + 4 y = 13.5

-

4 x + 3 y = 12.75
______________________

- x + y = 0.75 Add x to both sides

- x + y + x = 0.75 + x

y = 0.75 + x

4 x + 3 y = 12.75

4 x + 3 * ( 0.75 + x ) = 12.75

4 x + 2.25 + 3 x = 12.75

7 x + 2.25 = 12.75 Subtract 2.25 to both sides

7 x + 2.25 - 2.25 = 12.75 - 2.25

7 x = 10.5 Divide both sides by 7

x = 10.5 / 7 = 1.5

y = 0.75 + x = 1.5 + 0.75 = 2.25

the cost of hot dog = 1.5
the cost of hot hamburger = 2.25