First, since we do not know what the costs are for a hot dog, fries, and a small drink, we will just use a,b,c represented the cost for each of the item.
a = cost of a hot dog
b= cost of the fries
c = cost of a small drink
From all the information that you get from the questions, you can get the following relations for a,b,c.
a+b=1.6
b+c=1.65
c+a=1.75
then you can solve for a, b, and c
add the first equation to second equation, we will get
2a+b+c=1.6+1.75=3.35
from the second equation, you know that b+c=1.65
so 2a+(b+c)=2a+1.65=3.35
therefore 2a = 1.7
Thus
You will get a = 0.85
4/7/2014

Weicheng C.