Six green balls and four red balls are in a bag. A ball is taken from the bag, its color recorded, then placed back in the bag. A second ball is taken and its color recorded. What is the probability the two balls are the same color?

Guest Jul 2, 2018

#1**+2 **

There are 6 green balls and 4 red balls, making 10 total balls. The probability of picking a green ball first is \(\frac{6}{10}\) .

Since there are replacements, there will be still 10 balls in the bag. Now, for the second draw, you pick green again; making the probability, \(\frac{5}{10}\) . So, the probability of picking a green ball both times is \(\frac{6}{10}*\frac{5}{10}=\frac{30}{100}=\frac{3}{10}\) .

Next, the probability of picking a red ball is \(\frac{4}{10}\) . Doing the same as before, we get: \(\frac{4}{10}*\frac{3}{10}=\frac{3}{25}\) .

I'm leaving the next step up to you, to solve... What can we do after this?

tertre Jul 2, 2018