12 Days of Christmas GMAT Competition - Day 6: The average age of 100

Question

12 Days of Christmas GMAT Competition with Lots of Fun

The average age of 100 employees of an organization in the year 2005 was 30 years. In 2007, 20 employees left at the average age of 60 years. If no employee joined or left the organization over the next five years, what was the average age, rounded to the higher side, of all employees in 2010?

A. 23 years
B. 25 years
C. 26 years
D. 28 years
E. 29 years

Bunuel · Accepted Answer

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rvgmat12 · Answer

The average age of 100 employees of an organization in the year 2005 was 30 years. In 2007, 20 employees left at the average age of 60 years. If no employee joined or left the organization over the next five years, what was the average age, rounded to the higher side, of all employees in 2010?

A. 23 years
B. 25 years
C. 26 years
D. 28 years
E. 29 years

In 2007, the average age is 32 years.
32*100 = 3200

20 employees left at average age of 60 = 3200-1200 = 2000 (for 80 employees left) - average of 25 years

Average in 2010 = 25+3 = 28

D

saswatab · Answer

2005: Average age of 100 employees = 30 years and employees = 100
Therefore, sum of age of 100 employees - 100*30 = 3,000

2007: Average age of 100 employees = 30+2 = 32 and employees = 100
Average age of employees who left = 60, # of employees who left = 20
Therefore, sum of age of remaining 80 employees = 32*100 - 20*60 = 2,000
And, average age of these 80 employees = 2,000/80 = 25 years

2010: Average age of the remains employees = average age at 2007 + 3 = 25 +3 = 28 years

Answer Option D

lizabini · Answer

In 2005, the average age of 100 employees of an organization was 30 years,

x/100 = 30
x = 30*100 = 3000

In 2007, 20 employees left at the average age of 60 years,
y/20 = 60
y = 60*20 = 1200

Total age of employees remaining, ​
3000 + 100*2 - 1200 = 2000 (Adding 100*2 to account for all employees aging by 2 years)

Average age in 2007,
2000/80 = 25

Average age in 2010 if no employee joined or left the organization,
25+3 = 28

Therefore, the answer is D.

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DHRJ0032 · Answer

in year 2007 , the average of remaining 80 employees is 25
so after 3 years i.e in 2010, 
the average age of remaining employess will be 25+3=28

D it is

happypuppy · Answer

In 2005
Total Employees: 100 
Avg Age : 30
Total Age: 30,00

In 2007 before leaving
Total Employees: 100
Avg Age : 32
Total Age: 32,00

In 2007 after leaving
Total Employees: 80
Total Age: 32,00 - (20*60) = 2000
Avg Age : 2000/80 = 25

In next 3 years:
Avg age = 25 + 3 = 28

Answer (D)

KarishmaB · Answer

Use the method of deviations discussed here: https://anaprep.com/arithmetic-usefulne ... eviations/ Average age in 2005 was 30 years. Average age in 2007 will be 32 (because everyone will grow older by 2 years). When 20 employees with an average of 60 leave, they take away the excess of 28 each with them which was distributed among the other 80 employees. So the average will reduce by 20*28/80 = 7. Hence, new average in 2007 is 25 years. Average in 2010 will be 25 + 3 = 28 years because each employee will become older by 3 years. Answer (D)

Gemmie · Answer

The average age of 100 employees of an organization in the year 2005 was 30 years. In 2007, 20 employees left at the average age of 60 years. If no employee joined or left the organization over the next five years, what was the average age, rounded to the higher side, of all employees in 2010?

A. 23 years
B. 25 years
C. 26 years
D. 28 years
E. 29 years

In 2005, the total ages are  30 * 100 = 3000

In 2007
 
  The total ages are  3000 + (2*100) - 60 * 20 = 2000   
  The avg age is  2000 / 80 = 25   
In 2010, the avg age is  25+3=28

Answer D

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12 Days of Christmas GMAT Competition - Day 6: The average age of 100

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