Mike was in charge of a special event at the community center. A company donated 50 cases of bottled water, with 12 bottles in each case. If 520 people took a water bottle, how many water bottles were left?

Solution:

Number of bottles donated by Company = 50 cases

As in case there are 12 bottles.

So total number of bottles donated = 50 * 12=600 bottles

Number of water bottles taken by People = 520 bottle

Number of bottles left = 600 - 520=80 Bottles

This is a multiplication + subtraction problem

First we multiply to find out how much water there was to start with

50x12 = 600

Now we can subtract the 520 bottles that have been used from our total 600 bottles

600 - 520 = 80