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At Didymus Corporation there are just two classes of employe [#permalink]
20 Sep 2018, 07:33
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At Didymus Corporation there are just two classes of employees: Silver and Gold. The average salary of Gold is $56000 higher than that of silver employees. If there are 120 silver employees and 160 gold employees then the average salary for the company is higher than the average salary for the silver by A) 8000 B) 15000 C) 25000 D) 32000 E) 36000
Last edited by chetan2u on 12 Jan 2019, 06:28, edited 1 time in total.
Formatted the question




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Re: At Didymus Corporation there are just two classes of employe [#permalink]
20 Sep 2018, 07:50
The ratio of silver employees to gold employees is silver : gold = 120:160 = 12:16 = 3:4 If we divide the distance between the two averages by 7, then silver will be “four parts” away from the total average, and gold will be “three parts” away. The difference is $56,000, so that divided by 7 is $8000. That’s one part. Four parts would be $32,000, which has to be the distance from the silver average to the total average. C
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Re: At Didymus Corporation there are just two classes of employe [#permalink]
20 Sep 2018, 11:32
Carcass wrote: The ratio of silver employees to gold employees is
silver : gold = 120:160 = 12:16 = 3:4
If we divide the distance between the two averages by 7, then silver will be “four parts” away from the total average, and gold will be “three parts” away.
The difference is $56,000, so that divided by 7 is $8000. That’s one part. Four parts would be $32,000, which has to be the distance from the silver average to the total average.
C How can we take the algebraic approach?



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Re: At Didymus Corporation there are just two classes of employe [#permalink]
20 Sep 2018, 11:33
it is cumbersome. You should always try to use the fastest approach. Regards
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Re: At Didymus Corporation there are just two classes of employe [#permalink]
20 Sep 2018, 15:53
rajlal wrote: How can we take the algebraic approach? Assume a salary for Silver employees=x Now then salary of gold employees = x + $56,000. Average salary of of comapny is = \(\frac{160 (x+56000)+ 120x}{160+120}\) Difference between comapany average and silver =\(\frac{160 (x+56000)+ 120x}{160+120}x\)=\(\frac{160 (x+56000)+ 120x (160+120)x}{160+120}\)= \(\frac{160 (56000)}{160+120}=32000\)
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Re: At Didymus Corporation there are just two classes of employe [#permalink]
10 Jan 2019, 21:02
rajlal wrote: At Didymus Corporation there are just two classes of employees: Silver and Gold. The average salary of Gold is $56000 higher than that of silver employees. If there are 120 silver employees and 160 gold employees then the average salary for the company is higher than the average salary for the silver?
A) 8000 B) 15000 C) 25000 D) 32000 E) 36000 Please fix typo should be then the average salary for the company is how much higher than the average salary for the silver employees



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Re: At Didymus Corporation there are just two classes of employe [#permalink]
10 Jan 2019, 21:21
MAGOOSH OFFICIAL SOLUTION wrote: We can use this if we pick a value for the average salary for the silver employees. It actually doesn’t matter what value we pick, because averages will fall in the same relative places regardless of whether all the individual values are slid up and down the number line. The easiest value by far to pick is zero. Let’s pretend that the silver folks make $0, and the gold folks make $56. (I divided dollars by 1000 for simplicity).
Now, we also have to simplify the numbers of employees. We could reduce the number of employees as long as we preserve the relative ratio.
silver : gold = 120:160 = 12:16 = 3:4
So everything would be the same if we just had 3 silver employees and 4 gold employees. OK, now find the sums.
silver = 3*0 = 0
gold = 4*56
I am not even going to bother to multiply that out, because we know that the next step is to divide by 7, the total number of employees.
total average = 4*56/7 = 4*8 = 32
The average salary is $32,000, which is $32,000 higher than the average for the silver employees. Answer = (C)



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Re: At Didymus Corporation there are just two classes of employe [#permalink]
12 Jan 2019, 04:03
AE wrote: rajlal wrote: At Didymus Corporation there are just two classes of employees: Silver and Gold. The average salary of Gold is $56000 higher than that of silver employees. If there are 120 silver employees and 160 gold employees then the average salary for the company is higher than the average salary for the silver?
A) 8000 B) 15000 C) 25000 D) 32000 E) 36000 Please fix typo should be then the average salary for the company is how much higher than the average salary for the silver employees The question is correct from the source. If you have any problem I expect you to take it with Magoosh team and not bicker it with me. Bye bye



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Re: At Didymus Corporation there are just two classes of employe [#permalink]
12 Jan 2019, 04:35
Guys no need to pick some wasteful dull fights. Often the questions from NONofficial resources have typos. As well, those from OFFICIAL resources. As such, it is just a question. Wed o have on the board countless questions more. Move on. Thank you
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Re: At Didymus Corporation there are just two classes of employe [#permalink]
12 Jan 2019, 06:27
rajlal wrote: At Didymus Corporation there are just two classes of employees: Silver and Gold. The average salary of Gold is $56000 higher than that of silver employees. If there are 120 silver employees and 160 gold employees then the average salary for the company is higher than the average salary for the silver BY ?
A) 8000 B) 15000 C) 25000 D) 32000 E) 36000 you can use weighted average method too... ........gold.............silver average..x............x+56000... weights... 160.............120.. so company'S AVERAGE = \(x+56000*\frac{120}{120+160}=x+56000*\frac{120}{280}=x+200*120=x+24000\) difference in silver and company's average = (x+56000)(x+24000)=x+56000x24000=32000
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Some useful Theory. 1. Arithmetic and Geometric progressions : https://greprepclub.com/forum/progressionsarithmeticgeometricandharmonic11574.html#p27048 2. Effect of Arithmetic Operations on fraction : https://greprepclub.com/forum/effectsofarithmeticoperationsonfractions11573.html?sid=d570445335a783891cd4d48a17db9825 3. Remainders : https://greprepclub.com/forum/remainderswhatyoushouldknow11524.html 4. Number properties : https://greprepclub.com/forum/numberpropertyallyourequire11518.html 5. Absolute Modulus and Inequalities : https://greprepclub.com/forum/absolutemodulusabetterunderstanding11281.html




Re: At Didymus Corporation there are just two classes of employe
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