Help! More counting problems

1. Jul 8, 2006

Magotine

Hi,

I've done more questions. Hopefully the wordings on these word problems aren't vague.

Could someone take a look? I'm not sure if I've thought about the problem the right way.

Thanks v. much in advance.

File size:
24.5 KB
Views:
72
File size:
25 KB
Views:
45
2. Jul 8, 2006

arildno

Try to learn LATEX, don't use the doc-format

3. Jul 9, 2006

0rthodontist

In the first one, the confusion is that you only need 5 letters to define a 9 letter palindrome. If you know the first 5 letters are ABCDE, then you know the last 4 letters are DCBA. So you only get to choose the first 5 letters, so that's how many possibilities there are.

In the second one, count the number of bridges available at each step. First step: 3 bridges. Second step: 4 bridges. Third step (going back): three bridges because you can't use the one you came on. Fourth step: 2 bridges

Last edited: Jul 9, 2006