The average salary/head of all the workers in a workshop is Rs.1000, if the average salary/head of 10 technician is Rs.1200 and the average salary/head of the rest is Rs.820, the total no. of workers in the work-shop is ?  Pick:
A) 120 / 9
B) 140 / 9
C) 150 / 9
D) 190 / 9
E) 170 / 9

Rationale: let the total number of workers be y . so sum of salary for all workers = sum of salary of 10 technician + sum of salary for other y - 10 workers . 10 x 1200 + 820 ( y - 10 ) = 1000 y ⇒ 12000 + 820 y - 8200 = 1000 y ⇒ 180 y = 3800 ∴ y = 190 / 9 so total number of workers = 190 / 9 d
Answer: D