3. An advertising company charges $40 per half-page advertisement and $75 per full-page advertisement. Michael has a budget of $800 to purchase 13 advertisements. (a) Define a variable for each unknown and write a system of equations to represent the situation.
(b) How many half-page advertisements does Michael purchase? Show your work.
(c) How many full-page advertisements does Michael purchase? Show your work.

Saline iv fluid bags cost $64.20 for 24, 1000 ml bags from one supplier. a new supplier sells 500 ml bags for $2 each. the hospital uses about 10,000, 1000 ml bags each month. nurses report that about half of the bags are more than half full when they are discarded. if you are going to use only one supplier, which size bag provides the best deal, and how much will you save each month? compare the cost of the new supplier to the current one.