Question

There is a class of 40 students out of which 16 are girls. There are 27 students who are right-handed. How many minimum numbers of girls who are left-handed in this class?

(a) 17

(b) 56

(c) 23

(d) 3

This question was addressed to me in an internship interview.

My doubt stems from Addition Theorem on Probability in section Discrete Probability of Discrete Mathematics

Answer 1

Right option is (d) 3

To explain I would say: Number of girls in the class is 16. Number of left-handed pupils + Number of right-handed pupils = 40. So, Number of left-handed pupils + 27 = 40, Number of left-handed pupils = 13. Therefore, the minimum number of right-handed girls is 16 – 13 = 3.