Answer:
Store A and it would cost $32.40 (answer choice A)
Explanation:
Let's start by studying how much she would pay for a single balloon on each store:
In store A: (5 balloons for $6) then per each balloon: $6/5 = $1.2 per balloon.
In store BA: (13 balloons for $16.25) then per each balloon: $16.25/13 = $1.25 per balloon.
This shows us that the better price is in store A if she wants to pay as little as possible. Now, at that price, if she wants to buy 27 balloons, she will be paying (27 times $1.2): 27 * $1.2 = $32.40