Subject: General Aptitude · Chapter: Probability · Exam: · Marks: · Difficulty:
In a class, 30\% of the students offered English, 20\% offered Hindi and 10\% offered both. If a student is selected at random, what is the probability that he has offered English or Hindi ?
(a)$\frac{2}{5}$
(b)$\frac{3}{5}$
(c)$\frac{3}{4}$
(d)$\frac{3}{10}$
(e)None of these
Answer
Answer (as printed): A
Explanation
$P(E)=\frac{30}{100}=\frac{3}{10}, P(H)=\frac{20}{100}=\frac{1}{5}$ and $P(E \cap H)=\frac{10}{100}=\frac{1}{10}$. $P(E$ or $H)=P(E \cup H)$ $$=P(E)+P(H)-P(E \cap H)=\left(\frac{3}{10}+\frac{1}{5}-\frac{1}{10}\right)=\frac{4}{10}=\frac{2}{5} .$$
Explanation as extracted from the printed page; notation may be imperfect.