The clue to the item the guys are buying is included to the word that comes after buys.
- The item they are buying are the number digits.
Reasons:
The amount paid by William for the quantity of the item bought = $1
Amount paid by Billy for the quantity bought = $2
The price Billy paid is twice the price paid by William, therefore;
The quantity Billy bought is twice that William bought
Similarly, the quantity Willie buys is three times the quantity bought by William.
Which corresponds with;
William bought 1 (One digit)
Billy bought 99 (Two digits)
Willie bought 757 (Three digits)
- Which gives that the items bought are numbers (digits).
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