Question

which set of shapes can be arranged in 6 equal groups, with no shapes left over?

Explanation:

Step1: Count shapes in first set

There are 8 green circles. $8\div6 = 1\cdots\cdots2$, so it can't be evenly divided into 6 groups.

Step2: Count shapes in second set

There are 14 blue stars. $14\div6 = 2\cdots\cdots2$, so it can't be evenly divided into 6 groups.

Step3: Count shapes in third set

There are 12 red triangles. $12\div6=2$, it can be evenly divided into 6 groups with 2 triangles in each group.

Step4: Count shapes in fourth set

There are 10 blue squares. $10\div6 = 1\cdots\cdots4$, so it can't be evenly divided into 6 groups.

Answer:

The set of red triangles.