Determine how many integer solutions there are to a+b+c+d=19 if

0<=a<=5,

0<=b<=6,

3<=c<=7,

3<=d<=8

Printable View

- Feb 7th 2010, 07:58 PMjmedsyinclusion-exclusion principle question
Determine how many integer solutions there are to a+b+c+d=19 if

0<=a<=5,

0<=b<=6,

3<=c<=7,

3<=d<=8 - Feb 8th 2010, 07:39 AMPlato
This is an extremely tedious problem to do with

*inclusion/exclusion*!

It is easy to do with generating functions.

I will start you off with*inclusion/exclusion*.

The number of ways for condition a to happen is .

The number of ways for conditions c to happen is .

The number of ways for conditions a & c to happen together is .

Now to finish you have to figure for each of the other conditions in all possible combinations.

With generating functions we expand .

The coefficient of will be the answer.