Answer: In a group of 500 people, 40% liked orange and 60% liked apple. If 100 people liked both, we can calculate the number of people who don't like both using the following steps:
1. Calculate the number of people who like orange:
- 40% of 500 = (40/100) * 500 = 200 people
2. Calculate the number of people who like apple:
- 60% of 500 = (60/100) * 500 = 300 people
3. Since 100 people liked both orange and apple, we need to subtract this number from the total number of people who like orange and apple:
- 200 + 300 - 100 = 500 - 100 = 400 people
Therefore, there are 400 people who don't like both orange and apple out of the 500 people in the group.