If a bag contains 6 green balls and 3 red balls, what the probability of picking out 2 red, with and without replacement.

For the first ball the probability we pick a red ball is the same, it's the number of red balls divided by the total number of balls. Which in this case is 3/9. 

If we replace the balls the chance of picking out a 2nd red ball is still 3/9. So the total probability is 3/9 times 3/9 which is 1/9.

If we don't replace the chosen ball. The probability of picking a second is still the number of red balls divided by the new total number which is 2/8 or 1/4. Therefore the total probability is 1/4 times 3/9 which is 1/12.

Answered by Toby F. Maths tutor

20703 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve for x: x^2 + 6x + 8 = 0


Frank, Mary and Seth shared some sweets in the ratio 4:5:7. Seth got 18 more sweets than Frank. Work out the total number of sweets they shared.


How do I graph linear inequalities?


The probability of obtaining heads on a biased coin is 0.4. The coin is tossed 600 times. Write down the mean number of heads and the standard deviation of the number of heads.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences