Greg gave a glass of water to each person at dinner. he put more than 2 ice cubes in each glass. each glass had the same number of ice cubes. how many ice cubes could greg have used in all?

a. 13
b. 15
c. 17
d. 19

Think:  since every glass will receive more than 2 cubes, then consider 3 cubes.  Does 3 divide into any of the four given possible answers without a remainder?  Does 3 divide into 13 without a remainder?  Follow this process until you find the possible answer into which 3 divides without a remainder.
Eliminate 4, because none of the four given possible answers divides by 4 without leaving a remainder.  What about 5?   Can you divide any of the given possible answers by 5 without there being a remainder?

The first one is correct