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June 30, 2015

June 30, 2015

Posted by **-Z** on Thursday, April 15, 2010 at 9:17pm.

- Math -
**Reiny**, Thursday, April 15, 2010 at 9:29pmMake a list of combinations.

2 stamps: 1,9

number of ways to arrange = 2

3 stamps: 1,2,7 - 1,3,6 - 1,4,5 - 2,3,5

number of ways to arrange = 4(3!) = 24

4 stamps: 1,2,3,4 - that is all of them

number of ways to arrange = 1(4!) = 24

total number of ways = 2+24+24 = 50

- Math -
**Alex**, Tuesday, July 24, 2012 at 12:46pmTry doing it with casework.

Case: 1

1,9 x2

2,8 x2

3,7 x2

4,6 x2

2+2+2+2=8.

That's it for case one since Diane only has one stamp for each.

Case: 2

1,2,7 x6

1,3,6 x6

1,4,5 x6

2,3,5 x6

6+6+6+6=24.

Case: 3

1,2,3,4 x24

The total answer is 8+24+24=56.