Calendars cost $0.75 each, and date books cost $0.50 each. Cindy ordered a total of 500 promotional items and spent $300. How many of each item did she order?

You can work these in your head.  If all items were date books, the total would have been $250, but was actually $50 more than that. Adding a calendar to the mix instead of a date book adds $.25 to the order cost. So, to add $50, we need to trade 200 of the date books for calendars.  There are 200 calendars and 300 date books in the order. _____ Check   200*.75 + 300*.50 = 150 + 150 = 300.