An analyst will recommend a combination of 3 industrial stocks, 2 transportation stocks, and 2 utility stocks. If the analyst can choose from 5 industrial stocks, 4 transportation stocks, and 3 utility stocks, how many different combinations of 7 stocks are possible?
A. 12
B. 19
C. 60
D. 180
E. 720
OA:D
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An analyst will recommend a combination of
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From 5 industrial stocks, the number of ways to choose 3 = 5C3 = (5*4*3)/(3*2*1) = 10.NandishSS wrote:An analyst will recommend a combination of 3 industrial stocks, 2 transportation stocks, and 2 utility stocks. If the analyst can choose from 5 industrial stocks, 4 transportation stocks, and 3 utility stocks, how many different combinations of 7 stocks are possible?
A. 12
B. 19
C. 60
D. 180
E. 720
From 4 transportation stocks, the number of ways to choose 2 = 4C2 = (4*3)/(2*1) = 6.
From 3 utility stocks, the number of ways to choose 2 = 3C2 = (3*2)/(2*1) = 3.
To combine these options, we multiply:
10*6*3 = 180.
The correct answer is D.
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Hi NandishSS,
In these types of multi-combination questions, you normally just have to find the individual number of combinations for each element, then multiply the results together.
From the information provided, the number of combinations of...
Industrial stocks = 5C3 = 10 possible combinations
Transportation stocks = 4C2 = 6 possible combinations
Utility stocks = 3C2 = 3 possible combinations
(10)(6)(3) = 180 possible combinations of 7 stocks.
Final Answer: D
GMAT assassins aren't born, they're made,
Rich
In these types of multi-combination questions, you normally just have to find the individual number of combinations for each element, then multiply the results together.
From the information provided, the number of combinations of...
Industrial stocks = 5C3 = 10 possible combinations
Transportation stocks = 4C2 = 6 possible combinations
Utility stocks = 3C2 = 3 possible combinations
(10)(6)(3) = 180 possible combinations of 7 stocks.
Final Answer: D
GMAT assassins aren't born, they're made,
Rich
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From the given 5 industrial stocks, the number of ways to choose 3 industrial stocks = 5C3 = 5C2 = (5*4)/(2*1) = 10.NandishSS wrote:An analyst will recommend a combination of 3 industrial stocks, 2 transportation stocks, and 2 utility stocks. If the analyst can choose from 5 industrial stocks, 4 transportation stocks, and 3 utility stocks, how many different combinations of 7 stocks are possible?
A. 12
B. 19
C. 60
D. 180
E. 720
OA:D
Source-GMATPrep EP2
We know that nCr = nC(n-r); if r > n/2, you must use this equivalent to ease the caculation. Remeber that nPr not equal to nP(n-r)
From 4 transportation stocks, the number of ways to choose 2 transportation stocks = 4C2 = 4C2 = (4*3)/(2*1) = 6.
From 3 utility stocks, the number of ways to choose 2 utility stocks = 3C2 = 3C1 = 3.
Number of different combinations of 7 stocks = 10*6*3 = 180.
OA: D.
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We have a basic combination problem in which an analyst has to select 3 industrial stocks from 5, 2 transportation stocks from 4, and 2 utility stocks from 3. Let's determine the number of ways to select each type of stock.NandishSS wrote:An analyst will recommend a combination of 3 industrial stocks, 2 transportation stocks, and 2 utility stocks. If the analyst can choose from 5 industrial stocks, 4 transportation stocks, and 3 utility stocks, how many different combinations of 7 stocks are possible?
A. 12
B. 19
C. 60
D. 180
E. 720
OA:D
3 industrial stocks from 5: 5C3 = (5 x 4 x 3)/3! = (5 x 4 x 3)/(3 x 2 x 1) = 10 ways
2 transportation stocks from 4: 4C2 = (4 x 3)/2! = (4 x 3)/(2 x 1) = 6 ways
2 utility stocks from 3: 3C2 = (3 x 2)/2! = (3 x 2)/(2 x 1) = 3 ways
Since the analyst is choosing all 3 types of stocks, there are 10 x 6 x 3 = 180 ways to select the stocks.
Answer: D
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