How Many Ornaments?


It was one of those silly guessing games for a prize. How many 
Christmas tree balls were in the big bowl in the department store.
Surprisingly, there were only five guesses. Jim was five under, 
Susan was two under, Willy was the winner, Jack was one over, and
Alice was six over. The numbers were 26, 15, 18, 21, and 20. 

How many ornaments were in the bowl? 
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Answer:
20.