Question

A box contains 5 black and 5 red balls. Two balls are randomly picked one after another from the box, without replacement. The probability for both balls being red is

• A. $\frac{1}{90}$
• B. $\frac{1}{2}$
• C. $\frac{19}{90}$
• D. $\frac{2}{9}$

Answer 1

The correct option is D $\frac{2}{9}$

$\mathrm{Box}\begin{array}{c}5\mathrm{Black}\\ 5\mathrm{Red}\end{array}$
Probability for both balls being red (without replacement)

$=\frac{5}{10}.\frac{4}{9}=\frac{2}{9}$