A contractor hired workers to complete a job in 20 days. After 8 days, 5 workers quit, causing a 4-day delay. How many workers were hired initially?
Show answer & explanation
Correct answer: C
Explanation
If x workers complete the work in 20 days,
then the total work = 20 x (worker-days)
Work done in 8 days = 8 x
Remaining work
20 x − 8 x = 12 x
5 workers leave
Now workers = x − 5
The work was completed 4 days late, so the total time
20 + 4 = 24 days
Work was completed in the first 8 days, so the remaining time
24 − 8 = 16 days
Equation
Remaining work = workers × days
(x − 5) × 16 = 12 x
16 x − 80 = 12 x
4 x = 80
x = 20
Initial number of workers = 20