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Q.

The average salary of all the workers in a workshop is Rs.8000. The average salary of 7 technicians is Rs.12000 and the average salary of the rest is Rs.6000. The total number of workers in the workshop is:

 A.

20

 B.

21

 C.

22

 D.

23

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Solution:
Option(B) is correct

Let the total number of workers in the workshop = $x$

Given Average of all workers

\(=8000\Rightarrow \dfrac{8000}{x}\)

Average of 7 members = $12000 \Rightarrow 7 \times 12000 = 84000$

Average of remaining workers = $6000 \Rightarrow 6000 \times (x – 7) \Rightarrow 6000x – 42000$

Find out the total number of workers

$8000x = 84000 + 6000x – 42000$

$2000x = 42000$

$x = 21$

Therefore the total number of workers in the workshop is = 21.

Edit: For a formula involving such questions, check comment by SUHAIL AHMED.

Edit 2: For an alternative solution, check comment by Sravan Reddy.


(3) Comment(s)


NITHIN RAJ
 ()

U can solve easily using allegation

12000. 6000

8000

2000. 4000

1:2

So 7 technicians means 14 workers other than technician

So total

14+7= 21



Sravan Reddy
 ()

Additional burden due to 7 technicians $= 7*(12000-8000) = 28000$

Saved money from other workers = 2000 per head.

To balance => No. of other workers $= \dfrac{28,000}{2000} = 14$

Total $= 14+7 = \textbf{21}$



SUHAIL AHMED
 ()

Following this formula would save your time:-

$\text{Number of workers}$  $= \text{Number of officers} \times \left(\dfrac{\text{Average Salary of Officers} - \text{Mean Average}}{\text{Mean Average} - \text{Average Salary of Workers}}\right)$