In how many ways can 5 letters be posted in 3 post boxes, if any number of letters can be posted in all of the three post boxes?  Pick.
A) 5 C 3 B) 5 P 3 C) 5(3) D) 3(5) E) 2(5)
Explanatory Answer   Sampling with replacement   The first letter can be posted in any of the 3 post boxes. Therefore, we have 3 possibilities.   Similarly, the second, the third, the fourth and the fifth letter can each be posted in any of the 3 post boxes.   Each of the 5 letters has 3 possibilities because we can post any number of letters in all of the boxes.   Therefore, the total number of ways the 5 letters can be posted in 3 boxes is 3 * 3 * 3 * 3 * 3 = 3(5)   Choice 3(5)
<result>D</result>
In how many ways can 5 letters be posted in 3 post boxes, if any number of letters can be posted in all of the three post boxes?