Suyog wrote:and ?? time that rate for hours in excess of 40.

suyog, I don't think the question is complete. Can you verifyt the ?? marked portion in the question

sorry !!!
The question is:

A factory that employs 1,000 assembly-line workers pays each of these workers $5 per hour for the first 40 hours worked during a week and 3/2 time that rate for hours in excess of 40. What was the total payroll for the assembly-line workers for a week in which 30 percent of them worked 20 hours, 50 percent worked 40 hours, and the rest worked 50 hours?
(A) $180,000
(B) $185,000
(C) $190,000
(D) $200,000
(E) $205,000

IMO B

300 works for 20 hours. Amt paid = 300*5*20 = 30000
500 works for 40 hours. Amt paid = 500*5*40 = 100000
200 works for 50 hours.
Amt paid = Amt paid at regular rate for 40 hours + Amt paid at 3/2 rate for 10 hours

= 200*5*40 + 200*5*10*3/2 = 55000

Total amt paid = 185000