3.

Three students compared the number of hours they each studied for a test.
Based on this information, which statement is true?


a. 

Jackie studied 1 hour, because 4 − 3 = 1.


b. 

Mary studied 5 hours, because 3 + 4 = 7 and 7 − 2 = 5.


c. 

Veronica studied 2 hours more than Mary, because 4 − 2 = 2.


d. 

Jackie, Mary, and Veronica studied a total of 9 hours, because 2 + 4 + 3 = 9.
