Posted by Stuck on Wednesday, December 16, 2009 at 7:37pm.
A pizzeria offers 8 different ingredients on its pizza. Andy chooses 3 different ingredients from the 8 by drawing the names from a hat. What is the probability that Andy chooses either mushrooms or pepperoni or both among his three ingredients?
The answer is 9/14, but how do you get it?

Math  bobpursley, Wednesday, December 16, 2009 at 7:46pm
You can do it this way:
Pr(either m or P or both)=1Pr(neither M or P)
Pr(neither)=6/8*5/7*4/6= 120/336=40/112=20/56=10/28= 5/14
Pr(either m or P or both)=15/14=9/14 
Math  Stuck, Wednesday, December 16, 2009 at 7:55pm
Thank you! I always forget you can minus the complement from 1.