Subject: General Aptitude · Chapter: Probability · Exam: · Marks: · Difficulty:
Dev can hit a target 3 times in 6 shorts Pawan can hit the target 2 times in 6 shorts and Lakhan can hit the target 4 times in 4 shorts. What is the probability that at least 2 shorts hit the target [DMRC-Customer Relationship Assistant (CRA) Exam, 2016]
(a)$\frac{2}{3}$
(b)$\frac{1}{3}$
(c)$\frac{1}{2}$
(d)None of these
Answer
Answer (as printed): A
Explanation
Probability of hitting the target: Dev can hit target $\Rightarrow \frac{3}{6}=\frac{1}{2}$, Lakhan can hit target $=\frac{4}{4}=1$ Pawan can hit target $=\frac{2}{6}=\frac{1}{3}$ Required probability that at least 2 shorts hit target $$\begin{aligned} & =\frac{1}{2} \times \frac{2}{3}+\frac{1}{2} \times \frac{1}{3}+\frac{1}{2} \times \frac{1}{3} \\ & =\frac{1}{3}+\frac{1}{6}+\frac{1}{6}=\frac{4}{6}=\frac{2}{3} \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.