(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

From a bag containing 4 white and 6 black balls, 2 balls are drawn at random. If the balls are drawn one after the other, without replacement, find the probability that

The first ball is white and the second ball is black

2. Relevant equations

3. The attempt at a solution

First ball is white so the probability is 4/10; Second ball is black so the probability is 6/9. Hence the probability of first ball is white and the second ball is black is given by 4/10 X 6/9 = 24/90 when simplified gives 4/15.

But when i try in the following way

The probability of picking two balls from 10 balls is^{10}C_{2}that is 45.

The probability of first ball being white is^{4}C_{1}that is 4 and the second ball being black is^{6}C_{1 }that is 6, so the probability for the question is n(E)/n(S) = (4 X 6)/^{10}C_{2}= 24/45 which gives 8/15.

Please help me where i went wrong.

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Probability of picking a ball randomly from a group of balls

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