If 18 identical machines required 40 days to complete a job, how many fewer days would have been required to do the job if 6 additional machines of the same type had been used from the beginning?

Question

anonymous · Answer

each machine has a rate of 1/(18*40). 

6 more machines added, then
1/(18*40) = 1/(24 d)

solve for d and d = 30 days. Which means it will take 10 fewer days

anonymous · Answer

am not getting you.. any simple step...

anonymous · Answer

well, what if 18 machines can finish the job in 40 days, then,
in 40 days, each machine can do 1/18 job yes?

anonymous · Answer

yes

anonymous · Answer

got it now... :-) thanks...

anonymous · Answer

ok, i'll finish:
then in 1 day, each machine can do 1/(18 *40) job

then in 1 day, 26 machines can do 26/(18*40) job

which means it will take 26 machines 1/[26/(18*40)] = 30 days day, which means 10 days fewer

anonymous · Answer

bundle of thanks dear... :-)