How to solve a square + 10 X + 25​

This is the beginning of all probability problems.Memorize it:
Probability =        (number of ways to be successful) divided by       (total number of possibilities) .
When you draw one from a deck of cards, there are 52 total possibilities.
How many red queens are there ?
-- Queen of hearts-- Queen of diamonds
There are two of them.
Probability of drawing one from the deck = 2 / 52  =  1/26  =  about  3.8% .