AoPS Wiki talk:Problem of the Day/June 15, 2011
Problem
AoPSWiki:Problem of the Day/June 15, 2011
Solution
We can solve this problem by a bit of trial and error. We can guess she rode days and we get
since the mean is clearly
and there are
terms. That's a bit too small. We can add
to
and get
. That's still to small. Now, we add
to get
, the answer we want. We now count how many numbers are in the following list:
. Adding
to the list gives us
. Dividing by
gives us
. Subtracting
gives us
. Our list has
numbers. Since she started on a Monday, we must add
days. Our answer is