Question

A ball is drawn at random from a box containing 10 red, 30 white, 20 blue and 15 orange marbles. The probability of a ball drawn is white.........

• A. $\frac{1}{3}$
• B. $\frac{3}{5}$
• C. $\frac{11}{15}$
• D. $\frac{2}{5}$

Answer 1

Answer: (D)

$\frac{2}{5}$

Total number of balls in the box, $n\left(S\right)=10+30+20+15=75$

Number of white balls, 30

Hence the number of favourable outcomes for getting a white ball is, $n\left(E\right)=30$

Hence the probability of a ball drawn is white is, $\frac{n\left(E\right)}{n\left(S\right)}=\frac{30}{75}=\frac{2}{5}$