Subject: General Aptitude · Chapter: Probability · Exam: · Marks: · Difficulty:
A box contains 4 red, 5 green and 6 white balls. A ball is drawn at random from the box. What is the probability that the ball drawn is either red or green?
(a)$\frac{2}{5}$
(b)$\frac{3}{5}$
(c)$\frac{1}{5}$
(d)$\frac{7}{15}$
(e)None of these
Answer
Answer (as printed): B
Explanation
Total number of balls $=(4+5+6)=15$. $P($ drawing a red ball or a green ball $)=P($ red $)+P($ green $)$ $$=\left(\frac{4}{15}+\frac{5}{15}\right)=\frac{9}{15}=\frac{3}{5} .$$
Explanation as extracted from the printed page; notation may be imperfect.