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There is a company X that does not elect employees who are under 20 ye [#permalink]
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09 Mar 2017, 22:38
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33% (01:18) correct 67% (02:03) wrong based on 96 sessions
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There is a company X that does not elect employees who are under 20 years old. 10 percent of the total number of employees is at least 20 years old or older. Is the average age of the employees older than 30 years old? 1) 70 percent of the employees were more than 40 years old. 2) 25 percent of the employees were more than 60 years old.
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Re: There is a company X that does not elect employees who are under 20 ye [#permalink]
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10 Mar 2017, 02:13
let the total employees be 100 St 1: let 10% or 10 be of the age of 20 and let 70 be the age of 40 and 20 be the age of x. Average = (200+2800+ 20x)/100 = 30 +x/5. x can minimum be 20. hence the minimum average age will be 34. ANSWER
St 2: let 10% or 10 be of the age of 20 and let 25 be the age of 60 and 65 be the age of x. average = (200+1500+ 65x)/100 = 17 +13x/20. x can minimum be 20. hence the minimum average age will be 30.ANSWER
Option D



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Re: There is a company X that does not elect employees who are under 20 ye [#permalink]
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10 Mar 2017, 03:01
ByjusGMATapp wrote: let the total employees be 100 St 1: let 10% or 10 be of the age of 20 and let 70 be the age of 40 and 20 be the age of x. Average = (200+2800+ 20x)/100 = 30 +x/5. x can minimum be 20. hence the minimum average age will be 34. ANSWER
St 2: let 10% or 10 be of the age of 20 and let 25 be the age of 60 and 65 be the age of x. average = (200+1500+ 65x)/100 = 17 +13x/20. x can minimum be 20. hence the minimum average age will be 30.ANSWER
Option D Isn't the question incorrectly worded? If 10% of the total number of employees are greater than or equal to 20 years of age, how can 70% of the employees be over 40 years old or 25% of the employees be over 60 years old? Am i missing anything?



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Re: There is a company X that does not elect employees who are under 20 ye [#permalink]
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10 Mar 2017, 03:07
Vyshak wrote: ByjusGMATapp wrote: let the total employees be 100 St 1: let 10% or 10 be of the age of 20 and let 70 be the age of 40 and 20 be the age of x. Average = (200+2800+ 20x)/100 = 30 +x/5. x can minimum be 20. hence the minimum average age will be 34. ANSWER
St 2: let 10% or 10 be of the age of 20 and let 25 be the age of 60 and 65 be the age of x. average = (200+1500+ 65x)/100 = 17 +13x/20. x can minimum be 20. hence the minimum average age will be 30.ANSWER
Option D Isn't the question incorrectly worded? If 10% of the total number of employees are greater than or equal to 20 years of age, how can 70% of the employees be over 40 years old or 25% of the employees be over 60 years old? Am i missing anything? Yes it is. In fact if you look at the statement "There is a company X that does not elect employees who are under 20 years old". that means 100% of the employee are of age 20 years or older, not just 10%. I have solved the question based on certain assumptions



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Re: There is a company X that does not elect employees who are under 20 ye [#permalink]
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03 Apr 2017, 16:49
ziyuen wrote: There is a company X that does not elect employees who are under 20 years old. 10 percent of the total number of employees is at least 20 years old or older. Is the average age of the employees older than 30 years old?
1) 70 percent of the employees were more than 40 years old.
2) 25 percent of the employees were more than 60 years old. OFFICIAL EXPLANATION If you modify the original condition and the question, and assume that the total number of employees is 100, the question becomes “is the average age of the employees older than 30 years old?” This becomes the sum of the 100 employees’ ages > (30 years old)(100 employees) = 3,000 years old? And if you assume the minimum 10% as 20 years old, you get 10 employees * 20 years old = 200, which becomes the sum of the rest 90 employees’ ages > 3,000 years old – 2,00 years old = 2,800 years old? Then, for con 1), if it is 70% of the employees, it is 70, and (70)(40 years old) = 2,800 years old, so it is greater than 40 years old, hence yes, it is sufficient. For con 2), you should apply CMT 4 (B: if you get A or B too easily, consider D). If you assume that 75% of the total employees are all 20 years old and the rest 25% are 60 years old, the sum of total 100 employees’ ages = (75 employees)(20 years old) + (25 employees)(60 years old) = 3,000 years old, and since 75% is older than 60 years old, it is always yes and sufficient. Therefore, the answer is D.
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Re: There is a company X that does not elect employees who are under 20 ye [#permalink]
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03 Apr 2017, 19:49
ziyuen wrote: ziyuen wrote: There is a company X that does not elect employees who are under 20 years old. 10 percent of the total number of employees is at least 20 years old or older. Is the average age of the employees older than 30 years old?
1) 70 percent of the employees were more than 40 years old.
2) 25 percent of the employees were more than 60 years old. OFFICIAL EXPLANATION If you modify the original condition and the question, and assume that the total number of employees is 100, the question becomes “is the average age of the employees older than 30 years old?” This becomes the sum of the 100 employees’ ages > (30 years old)(100 employees) = 3,000 years old? And if you assume the minimum 10% as 20 years old, you get 10 employees * 20 years old = 200, which becomes the sum of the rest 90 employees’ ages > 3,000 years old – 2,00 years old = 2,800 years old? Then, for con 1), if it is 70% of the employees, it is 70, and (70)(40 years old) = 2,800 years old, so it is greater than 40 years old, hence yes, it is sufficient. For con 2), you should apply CMT 4 (B: if you get A or B too easily, consider D). If you assume that 75% of the total employees are all 20 years old and the rest 25% are 60 years old, the sum of total 100 employees’ ages = (75 employees)(20 years old) + (25 employees)(60 years old) = 3,000 years old, and since 75% is older than 60 years old, it is always yes and sufficient. Therefore, the answer is D. Hi, I'm relatively new to GMAT, and everybody seems to be using this "CMT" strategy, could you please send me a link where I can read more about this.



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Re: There is a company X that does not elect employees who are under 20 ye [#permalink]
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03 Apr 2017, 21:28
avinsethi wrote: ziyuen wrote: ziyuen wrote: There is a company X that does not elect employees who are under 20 years old. 10 percent of the total number of employees is at least 20 years old or older. Is the average age of the employees older than 30 years old?
1) 70 percent of the employees were more than 40 years old.
2) 25 percent of the employees were more than 60 years old. OFFICIAL EXPLANATION If you modify the original condition and the question, and assume that the total number of employees is 100, the question becomes “is the average age of the employees older than 30 years old?” This becomes the sum of the 100 employees’ ages > (30 years old)(100 employees) = 3,000 years old? And if you assume the minimum 10% as 20 years old, you get 10 employees * 20 years old = 200, which becomes the sum of the rest 90 employees’ ages > 3,000 years old – 2,00 years old = 2,800 years old? Then, for con 1), if it is 70% of the employees, it is 70, and (70)(40 years old) = 2,800 years old, so it is greater than 40 years old, hence yes, it is sufficient. For con 2), you should apply CMT 4 (B: if you get A or B too easily, consider D). If you assume that 75% of the total employees are all 20 years old and the rest 25% are 60 years old, the sum of total 100 employees’ ages = (75 employees)(20 years old) + (25 employees)(60 years old) = 3,000 years old, and since 75% is older than 60 years old, it is always yes and sufficient. Therefore, the answer is D. Hi, I'm relatively new to GMAT, and everybody seems to be using this "CMT" strategy, could you please send me a link where I can read more about this. MathRevolution, Could you help to explain? avinsethi, only mathrevolution official explanation using that strategy. I am not familiar with that as well.
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Re: There is a company X that does not elect employees who are under 20 ye [#permalink]
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04 Apr 2017, 07:26
This question needs rewriting!! The logic of the question doesn't even stand!




Re: There is a company X that does not elect employees who are under 20 ye
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04 Apr 2017, 07:26






