Question

An urn contains $10$ red and $8$ white balls. One ball is drawn at random. Find the probability that the ball drawn is white.

Answer 1

Total no. of balls in the urn is $18$ $(10$ red and $8$ white$)$

No. of white balls in the urn is $8$

Therefore, ${}^8{C}_1$( Selecting $1$ out of $8$ items) times out of ${}^{18}{C}_1$( Selecting $1$ out of $18$ items) a white ball is picked.

Let $E$ be the event of drawing a white ball from the urn.

We know that, $P\left(E\right)$ $=\frac{\text{(No.of favorable outcomes)}}{\text{(Total no.of possible outcomes)}}$$=\frac{{}^8{C}_1}{{}^{18}{C}_1}$$=\frac{8}{18}$$=\frac{4}{9}$