Deepthi Subbu wrote:Company A.s workforce consists of 10 percent managers and 90 percent software engineers. Company B.s workforce consists of 30 percent managers, 10 percent software
engineers, and 60 percent support staff. The two companies
merge, every employee stays with the resulting company, and
no new employees are added. If the resulting company's
workforce consists of 25 percent managers, what percent of
the workforce originated from Company A?
(A) 10%
(B) 20%
(C) 25%
(D) 50%
(E) 75%
Percentage of managers in A = 10%
Percentage of managers in B = 30%.
Percentage of managers in the MIXTURE of A and B = 25%.
Approach 1: ALLIGATION -- a very good way to handle MIXTURE PROBLEMS.
Step 1: Plot the 3 percentages on a number line, with the percentages for A and B (10% and 30%) on the ends and the percentage for the mixture (25%) in the middle.
A 40-------------25-----------30 B
Step 2: Calculate the distances between the percentages.
A 40-----
15-----25-----
5-----30 B
Step 3: Determine the ratio in the mixture.
The ratio of A to B in the mixture is the RECIPROCAL of the distances in red.
A : B = 5:15 = 1:3.
Thus, of every 4 managers in the mixture, 1 is from Company A, and 3 are from company B.
Thus:
A/total = 1/4 = 25%.
The correct answer is
C.
For more alligation problems, check here:
https://www.beatthegmat.com/ratios-fract ... 15365.html
Approach 2: Plug in the answers
Answer choice C: 25% from Company A
Let A = 100 employees and B = 300 employees.
Managers in A = 10% of 100 = 10.
Managers in B = 30% of 300 = 90.
Total managers/total employees = (10+90)/(100+300) = 100/400 = 25%.
Success!
Last edited by
GMATGuruNY on Mon Jun 03, 2013 3:38 pm, edited 1 time in total.
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