Question 468 of 480
In a survey of 50 newspaper readers, 40 read Champion and 30 read Guardian. How many read both papers?
Correct Answer:
D
Explanation
Assuming every reader reads at least one paper, n(C ∪ G) = 50. n(C ∪ G) = n(C) + n(G) - n(C ∩ G). So 50 = 40 + 30 - n(C ∩ G) → n(C ∩ G) = 70 - 50 = 20.