Question 327980
To solve this equation, you are going to need to write two equations using what you know to find out the cost of one burger platter and one hot dog platter.
First, you know that two burger platters and one hot dog platter costs $21:
2B + H = 21 (where B = hamburger platter, H = hot dog platter)
Second, you know two hot dog platters and one hamburger platter costs $18:
2H + B = 18
This can be rewritten as B = 18 - 2H
Now plug in the second equation into the first equation and solve for H:
2B + H = 21
2(18 - 2H) + H = 21
36 - 4H + H = 21
36 - 3H = 21
-3H = -15
H = 5
So one hot dog platter costs $5.
Now plug this into the first equation to find the cost of a hamburger platter:
2B + H = 21
2B + 5 = 21
2B = 16
B = 8
So a hamburger platter costs $8.
Now we want to find out how much two hotdog platters and two hamburger platters costs:
2H + 2B = C
2(5) + 2(8) = C
10 + 16 = C
26 = C
So the total cost of two hot dog platters and two hamburger platters is $26.