First, sort the items by price. Let x = the number of Chocolate Candy Bars that Cindy must purchase.
Attachment:
cookies.png [ 15.1 KiB | Viewed 587 times ]
Since we need the median to be $1.88, and there's not an item with that exact price, it must be an average between the items that cost 1.76 and 2.00. (This also hints that there's an even number of items total.)
The median is the middle number in a sorted list, so exactly half of the total number of items will be 2.00 and above, and the other half will cost 1.76 or below.
There are 12 items that are priced 2.00 and above.
There are (x + 10) items that are priced 1.76 and below.
x+10 = 12
x = 2