Hi All,
I have a quick question on a problem that appears in the MGMAT Word Translation book around Venn Diagrams. (for reference it's on page 133 of the 3rd edition; Guide # 4):
"Workers are grouped by their areas of expertise and are placed on at least one team. 20 workers are on the marketing team, 30 are on the sales teams, and 40 are on the Vision team. 5 workers are on both the marketing and sales teams, 6 workers are on both the sales and vision teams, 9 workers are on both the marketing and vision teams, and 4 workers are on all three teams. How many workers are there in total?"
So instead of using a Venn diagram, i was using the general formula:
Total # = A + B + C - (A and B) - (B and C) - (A and C)- 2 * (A & B & C) + other
Since we know each person is in at least one team, the last term is 0. by that formula:
Total # = 20 + 30 + 40 - 5 - 6 - 9 - 2 * (4) = 62
But the official answer works out to be 74 using the Venn diagram method. The Venn way makes sense but now sure what I'm doing wrong in getting the wrong answer w/ the formula?
Thanks!
MGMAT World Translation Question - Venn Diagrams
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- Robinmrtha
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Hi david...
your formula is wrong
Total # = A + B + C - (A and B) - (B and C) - (A and C)- 2 * (A & B & C) + other
it should be
Total # = A + B + C - (A and B) - (B and C) - (A and C) + (A & B & C) + other
=20 + 30+ 40-5-6-9+4 + 0(no others)
=74
Hope this helps
your formula is wrong
Total # = A + B + C - (A and B) - (B and C) - (A and C)- 2 * (A & B & C) + other
it should be
Total # = A + B + C - (A and B) - (B and C) - (A and C) + (A & B & C) + other
=20 + 30+ 40-5-6-9+4 + 0(no others)
=74
Hope this helps
-
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well I use the vein diagram and am getting 62.
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The powers of two are bloody impolite!!
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I think formula used by Robin and David is one and the same thing.i.e One can be derived from the other
It is interesting to note however that interpretation of (AandB) is different
n=> intersection
=> (AandB)= AnB-AnBnC----DAVID
=> (AandB)= AnB-------Robin
It is also important to note that a statement like the one below
if the statement was
It is interesting to note however that interpretation of (AandB) is different
n=> intersection
=> (AandB)= AnB-AnBnC----DAVID
=> (AandB)= AnB-------Robin
It is also important to note that a statement like the one below
means that we are also speaking about the people who are part of Marketing,Vision and Sales team5 workers are on both the marketing and sales teams
if the statement was
than it would have meant only members who are part of Marketing and Sales and not of Vision team5 workers are on both the marketing and sales teams ONLY
- ssmiles08
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I think in the WT book, they tell you to work with "all three" value first and then work your way up subtracting numbers.david2008 wrote:Hi All,
I have a quick question on a problem that appears in the MGMAT Word Translation book around Venn Diagrams. (for reference it's on page 133 of the 3rd edition; Guide # 4):
"Workers are grouped by their areas of expertise and are placed on at least one team. 20 workers are on the marketing team, 30 are on the sales teams, and 40 are on the Vision team. 5 workers are on both the marketing and sales teams, 6 workers are on both the sales and vision teams, 9 workers are on both the marketing and vision teams, and 4 workers are on all three teams. How many workers are there in total?"
So instead of using a Venn diagram, i was using the general formula:
Total # = A + B + C - (A and B) - (B and C) - (A and C)- 2 * (A & B & C) + other
Since we know each person is in at least one team, the last term is 0. by that formula:
Total # = 20 + 30 + 40 - 5 - 6 - 9 - 2 * (4) = 62
But the official answer works out to be 74 using the Venn diagram method. The Venn way makes sense but now sure what I'm doing wrong in getting the wrong answer w/ the formula?
Thanks!
S+M+V = 4
M+V = (9-4) = 5
S+V = (6-4) = 2
M+S = (5-4) = 1
V =40 -[ (V+S) + (M+V) + (S+M+V) ] = 40 - (11) = 29
S = 30 -[ (M+S) +(S+V) + (S+M+V) ] = 30 - (7) = 23
M = 20 - [ (M+S) + (M+V) + (S+M+V) ] = 20 - (10) = 10
now we have: 4+5+2+1+29+23+10 = 74