N1D8TNp21

Answer to Problem 21:

Students may approach this problem in different ways.  Some students will need to write the days and what will be served on those days.  Others will use common multiples to solve the problem.  Encourage each method.

Common Multiple:

Hamburgers:   6, 12, 18, 24, 30, 36

Fries:               8, 16, 24, 32

Cake:               4, 8, 12, 16, 20, 24, 28, 32 

The common multiple is 24.  It will be 24 more days before hamburgers, fries, and cake are served on the same day.