Question 781974
6 workers can clean 40 cars in 4 days. 
1 worker would take 6 times as long, so
1 worker can clean 40 cars in 24 days
It would take 48 times as many workers to
clean that many cars in 1/48 of that time, so
48 workers can clean 40 cars in 24/48, or 1/2 day