Question

A person draws out two balls successively form a bag containing 6 red and 4 white balls. The probability that at least one of them will be red, is

• A. $\frac{78}{90}$
• B. $\frac{30}{90}$
• C. $\frac{48}{90}$
• D. $\frac{12}{90}$

Answer 1

Answer: (A)

$\frac{78}{90}$

Required probability
$=P(W,R)+P(R,W)+P(R,R)$
$=\frac{6}{10}\times \frac{4}{9}+\frac{4}{10}\times \frac{6}{9}+\frac{6}{10}\times \frac{5}{9}$
$=\frac{24+24+30}{90}=\frac{78}{90}$