Question

There are 4 torn books in a lot consisting of 10 books. If 5 books are seleceted at random what is the probability of presence of 2 torn books among the selected?

• A. 1/3
• B. 4/21
• C. 10/21
• D. 2/7

Answer 1

The correct option is C

10/21

Total Sample space: ${}^{10}{C}_5=252$

Favourable cases: ${}^4{C}_2{\times }^6{C}_3=120$

Hence $P\left(E\right)=\frac{120}{252}=\frac{10}{21}$