Question 831956
20 cent coins?  Odd question.
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If there are more than 5 coins, there are at least 6.
If there are less than 12 coins, there are no more than 11.
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Obviously, the greater number of .50 pieces, the higher the total value.  
Let's look at the possibilities:
11 .50 pieces = 5.50
10 .50 pieces = 5.00
10 .50 pieces + 1 .20 = 5.20
9 .50 pieces = 4.50
9 .50 pieces + 2 .20 = 4.90
9 .50 pieces + 1 .20 = 4.70
8 .50 pieces = 4.00
7 .50 pieces = 3.50
6 .50 pieces = 3.00

and so on...