Show that at least ten of any 64 days chosen must fall on the same day of the week. We prove this using the method of contradiction. This would account for at most 9 x 7 63 days, but we have chosen 64 days. Suppose there are nine or fewer days that fall on the same day of the week. This would account for at least 10 x 7 70 days, but we have chosen only 64 days. This contradiction shows that at least 10 of the days must be on the same day of the week. Suppose there are 10 or fewer days that fall on the same day of the week Reset