Question

A urn contain $10$ black and $5$ white balls. Two balls are drawn from the urn one after the other without replacement. What is the probability that both drawn balls are black?

Answer 1

Here,

total number of balls $=15$

number of black balls $10$

number of white balls $5$

So, the probability of the ball drawn is black $=\frac{10}{15}$

Required probability $=\frac{10}{15}\times \frac{9}{14}$$=\frac{3}{7}$