Math
posted by kelsey .
To win one million dollars, you must draw two cards whose sum is nine, from a stack of cards numbered through 10. After the first draw you replace the card and shuffle the stack again for the the second draw. What is the chance that your two cards will have a sum of nine.?

Wow, where can I play this game????
I will assume that 0 is not one of the cards.
number of possible pairs is 10x10 or 100
pairs which have a sum of 9 are:
18, 27, 36, 45, 54, 63, 72, and 81 or 8 of them
so prob that it will have a sum of 9 is 8/100 or 2/25
let me at this game!!!