Question

Set A contains all integers from 50 to 100 inclusive, Set B contains all integers from 69 to 138 exclusive. How many integers are included in both Set A and Set B.

A.29
B.30
C.31
D.32

Answer 1

Answer: C. 31

Explanation:
Set A contains [50, 51, 52, … , 99, 100]. Set B contains [70, 71, 72, … , 136, 137]

Notice that Set B and Set A have an overlap from 70 to 100. So that is 31 elements in total. Hence the set A intersect B is [70, 71, 72, … , 99, 100] which is 31 elements.

Cheers.