Question

Mrs. Shelton doesn't have enough marking pens for everyone in class. Every 2 students share a green pen and every 4 students share a red pen. If she has
15 marking pens in all how many students are in Mrs. Shelton's class?

Answer 1

Does each student have access to one or to two marking pens?

Answer 2

there is 20 kids min the class

Answer 3

What a great question! One has to begin by assuming that all students have access to both a red and a green pen. We know that the sum of the pens is 15, and that "the number of students" must be divisible by both 4 and 2. In fact, the sum of the quotients of the "number of students" divided by first 4, then 2, must equal 15. One of my students drew a nice diagram of how this can work.