On the island of Mumble, the Mumblian alphabet has only 5 letters, and every word in the Mumblian language has no more than 3 letters in it. How many words are possible? (A word can use a letter more than once, but 0 letters does not count as a word.)
There's an equation to this... l just can't put my finger on it.
The work can be 1,2 or 3 letters long.
If it is 1 letter then there are 5 choices
If it is 2 letters then there are 5 choices for the first letter and then 5 choices for the second letter.
That is 5*5 = 25 posibilities
If it is 3 letters then there are 5 choices for the first letter and then 5 choices for the second letter and 5 for the third
That is 5*5*5 = 125 posibilities
So that makes
5+25+125 = 155 possible words