A probability question

Question

a thumbtack lands point up with probability 1/2 and points down with probability 2/3 three thumbtacks are thrown together what is the probability they all land point up?

Answer 1

 

There are 3 thumbtacks.  The individual probability of each one (individually) landing point up is 1/2.

To find the probability of all three landing point up, we multiply the individual probabilities.

 

   1/2 • 1/2 • 1/2  = 1/8