On the first day of school, the school store had 100 pencils for sale at $1 each. at the end of the week, there were 90 pencils left. the second week, the price of pencils dropped to $.75 each. at the end of the week, there were 75 pencils left. the store dropped the price $.25 each week, and at the end of the fourth week, there were no pencils left. which price was the market clearing price?