Today’s Challenge Problem

Posted: July 25th, 2006 | Author: Jeff | Filed under: Uncategorized | 4 Comments »

If the probability that a visitor at a store buys a pack of gum is 30%. Then if 3 visitors come to the store today, what is the probability that exactly two will buy a pack of gum?

A) 0.343 B) 0.147 C) 0.189 D) 0.063 E) 0.027

4 Comments on “Today’s Challenge Problem”

1 Allan said at 8:15 am on July 26th, 2006:
d
2 Administrator said at 5:13 pm on July 26th, 2006:
Answer: b
0.3 x 0.3 x 0.7 x C(3, 2) = 0.3 x 0.3 x 0.7 x 3 = 0.189

The C(3,2) is necessary because there are a total of 3 different ways where two buy and one doesn’t.
3 Allan said at 7:08 pm on July 26th, 2006:
Dammit! I better get the next one.
4 cT! said at 6:15 am on July 28th, 2006:
And this is why I keep my answers to myself. I don’t wanna embarass myself.