there are 35 students in art class and 57 students in dance class. Find the number of students who are either in art class or in dance class

hope it helps you

Step-by-step explanation:

Let

A be the set of students in art class

B be the set of students in dance class

n(A) = 35    

n(B) = 57      

a) When 2 classes meet at different hours and n(A ∩ B) = 12 we have:

n(A ∪ B) = n(A) + n(B) - n(A ∩ B) = 35 + 57 - 12 = 80

b) When two classes meet at the same hour we have A∩B = ∅ that is n(A ∩ B) = 0 and

n(A ∪ B) = n(A) + n(B) - n(A ∩ B) = n(A) + n(B)  = 35 + 57 = 92

b.-4 units

all you   do is count how many times you move

the answer is two. hope this !