Posted by John on .
I don't get how to do this...can anyone help?
1. In a large box are 20 pingpong ballsâ€”10 of them are red and numbered 1 through 10, and the other 10 of them are green and also numbered 1 through 10. Two balls are selected from the box without replacement.
1.
a.Find the probability that the first ball selected is red and even.
2.
b.Find the probability that the first ball selected is red OR even.

Math/Statistics 
PsyDAG,
1a. There are 5 balls (red and even) out of the 20.
2b. Only the 5 green odd balls should not be chosen out of the 20. What proportion remains?
You have no indication of what you desire on the second draw.
I hope this helps. Thanks for asking.