[C] 0.05b + 0.25s + 0.4n = 20
b = balloons
s = streamers
n = noisemaker
Since they already give us the price of each item we just need to add a variable at the end of each one since we don't know how many of each item is bought. Adding the costs of all the party supplies should not go over $20. We can automatically eliminate B and D. We can also eliminate A because the prices of each item are incorrect. Therefore, C is the correct answer.
Best of Luck!
