Friday, February 29, 2008

Today's Slides and Homework: February 29

Here they are ...



4 comments:

CowMilk said...
This comment has been removed by the author.
CowMilk said...

Mr.K
I don't understand the homework question on slide 7 . Did you count # 0 when the last number is 5 ? I think it should be 8 . 10 . 1=80

???

Mr. Kuropatwa said...

@cowmilk: We are trying to find how many 3 digit numbers there are ending in 5 AND all the digits CAN repeat. SO:


9   10   1
1st 2nd 3rd

3rd digit: must be "5", only 1 way to do this.

1st digit: can be anything except zero (1, 2, 3, 4, 5, 6, 7, 8, 9), 9 ways to do this.

2nd digit: can be any digit including zero (0, 1, 2, 3, 4, 5, 6, 7, 8, 9), 10 ways to do this.

Does that make sense?

CowMilk said...

yap ..thank you ^^