Two family reunions are happening at the Park Avenue hotel, the Oates reunion and the Hall reunion. All 100 guests at the hotel attend at least one of the reunions. If 40 people attend the Oates reunion and 70 people attend the Hall reunion, how many people attend both reunions Choose the correct choice from the following answers:
A) 2
B) 5
C) 10
D) 16
E) 22

Rationale: no of people in oates reunion = 40 no of people in hall reunion = 70 attending both = x all guests attend at least one . therefore , 100 = 40 + 70 - ( both ) both = 10 answer c
Answer: C