There are 45 students in Class 3, Class 3, 26 students take part in the math contest, 22 students take part in the composition contest, 12 students both take part. How many students participated in these two projects?
Solution: It is known that there are 45 students in 3 classes, 26 students in 3 classes take part in the math contest and 22 students take part in the composition contest.
The number of people who get both = the number of people who take part in the math contest+the number of people who take part in the composition contest-the total number of class three and three.
=26+22-45
=48-45
=3 people
A: There are three people participating in both events.