A creative entrepreneur has created a novelty soap called jackpot. Inside each bar of jackpot soap is a rolled-up bill of U.S. currency. There are 1000 bars of soap in the initial offering of the soap. Although the denomination of the bill inside a bar of soap is unknown, the distribution of bills in these first 1000 bars is given in the following table:

How many bars of soap does a customer have to buy so that, on average, she has purchased two containing a $50 or $100 bill?

Bill Denomination Number of Bills $1 $5 520 260 $10 $20 $50 130 60 29 $100 Total 1 1000