Question

At a concession stand, three hot dog(s) and two hamburger(s) cost $7.50, two hot dog(s) and three hamburger(s) cost $8.75. Find the cost of one hot dog and the cost of one hamburger

Answer 1

Explanation:

If 3 HD and 2HB cost $7.50

2 HD and 3HB cost $8.75

Let,y be HD

Y be HB

So 3y + 2x = $7.50. Eqn 1

2y + 3x = $8.75. Eqn 2

Solve simultaneously

Make x the subject in Eqn 1

3y + 2x = 7.50

2x = 7.50 - 3y

Devide by the coefficient of x

2x/2 = (7.50 - 3y) / 2

X = (7.50 - 3y) /2 Eqn 3

Put Eqn 3 into 2

2y + 3(7.50 - 3y) / 2 = 8.75

2y (22.5 - 9y) / 2 =8. 75

Multiply by the lcm of the denominators

2y x 2 + ((22.5 - 9) / 2) x 2 = 8.75 x2

4y + 22.5 - 9y = 17.50

Group like terms

22.5 - 17.50 = 9y - 4y

5 = 5y

5/5 = (5y) / 5

1 = y Eqn 4

Therefore 1 HD is $1

Put Eqn 4 into eqn 3

X = (7. 50 - 3y) / 2

X = (7.50 - 3(1)) / 2

X = 4.5 / 2

X = 2.25

Therefore 1 HB is $2.25