Question

How many ways are there to choose three donuts from 4 varieties if there must be an odd number of glazed donuts? the number of glazed must be 1 or 3?

Answer 1

1 glazed and 2 others or 3 glazed and 0 others

1 x 3 x 3 + 1 x 1 x 1

9 + 1

10

Answer: 10