1. The problem statement, all variables and given/known data There is total of 300 balls in the basket, 30 of them is red (rest is white). If we picked up, randomly, 4 balls, what is the probabilty that all of them is red ? 2. The attempt at a solution For one picked ball, probability that it's red is 30/300 = 1/10. If picked ball is red, probabilty for next ball is 29/299,and so on, 28/298, 27/297. Is that correct ? And, what next ?