If a job takes 12 men 4 hours to complete how long should it take 15 men to complete the job?

Answer 1

answer:

for a problem like this you have to compute how many person-hours it will take to complete the job and then it's easy to figure out the total time.

so,

let j = total job person-hours = 12 people * 4 hours = 48 person-hours

so, we know we need 48 person-hours to complete the entire job. so, given that we have now 15 people to complete the job,

let t = total time to complete job with 15 people = 48 person-hours / 15 people = 3.2 hours, or 3 hours 12 minutes

therefore, for a job that takes 12 people 4 hours, assuming there is no particular constraint on the amount done per person, the job can be done in 3 hours 12 minutes with 15 people. (for instance, although one woman can have a baby in nine months, 9 women can't have a baby in one month)

previous answer:

I think it'll be 1hour

my own conclusion