Answer: You might have messed up the question
Here is the answer based on your question
W (Bottled water) = 7/2$
N (Cheese Nachos) = -1/2$
Explanation:
2W + 3N = $5.50
3W + 2N = $9.50
Find the common number and subtract them. In order to find isolate the water bottles or nachos. I will do water bottles
15 (2W + 3N = $5.50)
10 (3W + 2N = $9.50)
30w + 45N = $82.5
Minus
30W + 20N = $90
= 25N = -12.5
N = -1/2$
Substitute for N
3W + 2(-1/2) =9.5
3w -1 = 9.5
3w - 10.5
w = 7/2$