Each letter in the word Massachusetts is written on a card T

Each letter in the word Massachusetts is written on a card. The cards are placed in a basket. What is the probability of selecting two S\'s if the first card is replaced before selecting the second card?

Solution

It\'s a probability of 16 out of 169.

There are 13 letters in MASSACHUSETTS. 4 of the 13 are the letter S, so there is a 4 in 13 chance to draw an S. Since the first card is replaced, there is still a 4 in 13 chance of drawing another S. So the combined probability is 4/13 x 4/13 = 16/169