Question

A bag contains $7$ red, $5$ white and $3$ black balls. A ball is drawn at random from the bag. Find the probability that the drawn ball is
$\left(i\right)$ Red or White
$\left(ii\right)$ Not black
$\left(iii\right)$ Neither white nor black

• A. $\left(i\right)\frac{1}{5}\left(ii\right)\frac{3}{7},\left(iii\right)\frac{7}{13}$
• B. $\left(i\right)\frac{4}{5}\left(ii\right)\frac{4}{5},\left(iii\right)\frac{7}{15}$
• C. $\left(i\right)\frac{1}{5}\left(ii\right)\frac{5}{8},\left(iii\right)\frac{7}{17}$
• D. $\left(i\right)\frac{4}{5}\left(ii\right)\frac{7}{9},\left(iii\right)\frac{7}{19}$

Answer 1

The correct option is B $\left(i\right)\frac{4}{5}\left(ii\right)\frac{4}{5},\left(iii\right)\frac{7}{15}$

Since, total no. of balls = 7+5+3 = 15
(i) No. of balls that are red or white = 7+5 = 12
$\therefore$ Required probability = $\frac{12}{15}=\frac{4}{5}$
(ii) No. of balls that are not black = 7+5 = 12
$\therefore$ Required probability = $\frac{12}{15}=\frac{4}{5}$
(iii) No. of balls that are neither white nor black = 7
$\therefore$ Required probability = $\frac{7}{15}$