Answer:
a or b
Step-by-step explanation:
if I did the math right it's a but I tried another way and got b, so I'm sorry if that was no help at all
and 
use the second expression to calculate the left-hand side of the first equation:

Add 10 to both sides if this equation to get

and divide both sides by 2

this proves that x = 17, give the two initial equations
Answer:
Sodas: 160
Hot Dogs: 80
Step-by-step explanation:
Sodas: s
Hot Dogs: d
s+d=240
s=2d
3d=240
d=80
s=160