A hamburger costs twice as much as a hot dog. Three hamburgers and two hot dogs cost $21. Choose the system of linear equations that represents this problem.

A. 2y=x
2x+3y=21

B. y=2x
2x+3y=21

C. x=2y
3x+2y=21

D. y=2x
3x+2y=21

C

Step-by-step explanation:

Hamburger = Hotdog x 2

3(Hamburger) + 2(Hotdog) = 21

Now replace with x (Hotdog) and y (Hamburger)

y = 2x

3y + 2x = 21

x = 2

step-by-step explanation:

if sr parallel to ba then the sides bc and ac are in proportion, that is

= ← substitute values

= ( cross- multiply )

27x = 6(4x + 1)

27x = 24x + 6 ( subtract 24x from both sides )

3x = 6 ( divide both sides by 3 )

x = 2