Average Practice Test 4

Let the number of workers = x
Average salary of all the workers x = Rs 850
Total salary of all the workers = Rs 850x
Average salary of seven technicians = Rs 1,000
Total salary = 7 × 1,000 = Rs 7,000
Average salary of ( x - 7) workers = Rs 780
Total salary = (x - 7) 780
According to the statement,
$850\mathit{x}=7,000+\left(\mathit{x}-7\right)780$
$850\mathit{x}=7,000+780\mathit{x}-5,460$
$850\mathit{x}-780=7,000-5,460$
$70\mathit{x}=1,540$
$\mathit{x}=22$ workers