Answer: 15 ways.
Explanation:
Total number of hats owned =6
The number of hats taking on vacation=2
To find the different ways to choose 2 hats from 6, we use combination with n=6 and r=2, we get
The number of ways to choose 2 hats from 6=


Hence, in 15 ways we can choose 2 hats from 6 hats.