<PRE><B>Question 433374</B>
The trick is to find the number in each
separate little area of the 3 interlocking circles
There are 7 of these little areas
The center is the number that grew all 3 types.
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Label the circles T,C, and Z
T = 69
C = 25
Z = 30
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T and C , but not Z = 18 - 12
18 - 12 = 6
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T and Z, but not C = 21 - 12
21 - 12 = 9
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C and Z, but not T = 14 - 12 
14 - 12 = 2
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The fact that 12 grew none of T,C, or Z can
be shown by a circle around the Venn diagram
with a 12 in it
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Those who grew:
Only T = 69 - (6 + 9 + 12)
Only T = 42
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Only C = 25 -(6 + 2 + 12)
Only C = 5
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Only Z = 30 -(9 + 2 + 12)
Only Z = 7
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Any question can now be answered, for instance:
How many growers of T,C, &amp; Z are there?
42 + 5 + 7 + 6 + 9 + 2 + 12 = 83
How many  grew exactly 2 veggies?
6 + 9 + 2 = 17</PRE>