A Bag Contains 7 White, 5 Black and 4 Red Balls. If Two Balls Are Drawn at Random, Find the Probability That:(I) Both the Balls Are White - Mathematics

A bag contains 7 white, 5 black and 4 red balls. If two balls are drawn at random, find the probability that both the balls are white

Solution

Out of 16 balls, two balls can be drawn in 16C2 ways.
∴ Total number of elementary events = 16C2 = 120

Out of seven white balls, two white balls can be chosen in 7C2 ways.
∴ Favourable number of ways = 7C2
Hence, required probability =

$\frac{^{7}{}{C}_2}{^{16}{}{C}_2} = \frac{21}{120} = \frac{7}{40}$

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APPEARS IN

RD Sharma Class 11 Mathematics Textbook
Chapter 33 Probability
Exercise 33.3 | Q 15.1 | Page 46