A bag contains $4$ white and $3$ red balls. Two draws of one ball each are made without replacement. Then the probability that both the balls are red is
$\frac{1}{7}$
$\frac{2}{7}$
$\frac{3}{7}$
$\frac{4}{7}$
Three vertices are chosen randomly from the seven vertices of a regular $7$ -sided polygon. The probability that they form the vertices of an isosceles triangle is
Three cards are drawn at random from a pack of $52$ cards. What is the chance of drawing three aces
Three squares of a chess board are chosen at random, the probability that two are of one colour and one of another is
In a box there are $2$ red, $3$ black and $4$ white balls. Out of these three balls are drawn together. The probability of these being of same colour is