Pigeonhole Principle: A computer is used for 99 hours....

[Guest]

Here it is:

A computer is used for 99 hours over a period of 12 days, an integral number of hours each day. Show that on some pair of 2 consecutive days, the computer was used for at least 17 hours.

I'm still lost on this, any help would be appreciated.

 

[galactus]

What it is asking is, out of a set of 12 integers that sum to 99, there is a subset of 2 integers which equal 17.

 

[Guest]

So is the set up something like C(12, 2) = 66, so some number of subsets out of a possible 66 that equal 17 ?