In a survey, it was observed that 20 students read newspapers and 35 read novels. If 40 of the students read either newspapers or novels, what is the probability of the students who read both newspapers and novels?

A.
(frac{1}{2}) 
B.
(frac{2}{3}) 
C.
(frac{3}{8}) 
D.
(frac{3}{11})
Correct Answer: Option C
Explanation
40 = 20 – x + x + 35 – x
40 = 55 – x
x = 55 – 40
= 15
∴ P(both) (frac{15}{40})
= (frac{3}{8})