Question

A box containes 2 black and 2 white ball then probablity of selecting 2 balls of the same colour

Answer 1

total no. of balls= 4
total no. of same colour balls ( either white or black)= 2
therefore, probability of selecting 2 balls of the same colour =
$\frac{total \: no. \: of \: same \: colour \: of \: balls}{total \: no. \: of \: balls}$
$= \frac{2}{4}$
$= \frac{1}{2}$

Answer 2

1/3.....................