i need a solution for this type of question.can anyone tell me the working steps or the description of the problem.
2007-08-07 04:54:42 · 11 answers · asked by lavender 1 in Science & Mathematics ➔ Mathematics
hey but the given to this ques was 7 and a half hours
2007-08-07 05:18:45 · update #1
Thirty men take 20 days to complete a job working 9 hours a day. How many hour a day should 40 men work to complete the job?
hey sin dis is the complete ques
2007-08-07 05:20:37 · update #2
Wow! Very confusing? Your question is missing one bit of information that needs to be clarified (number of days the 40 men work to complete that same job). I assumed 20 days again. The answer then would be 6.75 hours per day.
How I solved it:
1) (# men) x (# days) x (# hours/day) = Total hours to complete the job.
2) Calculate total man-hours to complete the initial job. 30 men x 20 days x 9 hours/day = 5,400 total man-hours.
3) If the total job takes 5,400 hours to complete you just plug that back into your first equation this time using 40 men instead of 30:
(40 men) x (20 days) x ? hours = 5,400 total hours
divide both sides by 40
divide both sides by 20
Hours = 6.75
This passes the sanity test. If you have more people working on the job (40 versus 30) it should take less time to complete the same job (6.75 hours versus 9 hours).
2007-08-07 05:11:52 · answer #1 · answered by Sin™ 6 · 0⤊ 0⤋
if 30 men need 180h to complete the job, 40 men will need less time,ie 180(3/4)h = 135h to complete the same job. if the number of days needed to complete the job is constant, number of hours per day should 40 men work= 135/20 = 6.75h.
2007-08-07 05:07:30 · answer #2 · answered by tyz 1 · 1⤊ 0⤋
*Thirty men take 20 days to complete a job working 9 hours a day.How many hour a day should 40 men work to complete the job?
2007-08-10 06:14:08 · answer #3 · answered by Anonymous · 0⤊ 0⤋
As soon as you hired the 10 extra men, 10 of the original 30 decided to start doing nothing all day, so it still takes 20 days to do the job.
2007-08-07 04:59:21 · answer #4 · answered by Bill W 【ツ】 6 · 0⤊ 0⤋
1 man actually completes the job while the others stand around pretending to be working and comparing each others work stories and women stories...none of which they have.
ANSWER: 1 man = 20 days = 9 hrs/per day = complete job = 2 super size bottles of Tylenol = 20-40oz. malt liquors = 1 divorce = 1/2 paycheck.
It's amazing how math works.
2007-08-07 05:05:39 · answer #5 · answered by Not Crazy 1 · 0⤊ 0⤋
repost the complete question...
"How many hours a day" is inversely proportional to how many men there are. The 20 days to complete the job is a constant, so it doesn't get used in the answer. What matters is the man-power required for the job:
9 hrs * 30men = x*40men
x=270(man-hr)/40man = 6.75 hrs (6hr 45min)
2007-08-07 04:57:46 · answer #6 · answered by anotherhumanmale 5 · 0⤊ 0⤋
20.9.30/40 =5400/40
=540/4=270/2=135 hours.
135/9=15 days
2007-08-07 05:05:01 · answer #7 · answered by iyiogrenci 6 · 0⤊ 0⤋
30 men * 9 hours=270 man-hours.
270 man-hours * 20days = 5,400hours total.
5,400 hours / 40 men = 135 man-hours.
Assuming they work 20 days on this project as well (you didn't specify):
135 man-hours / 20 days = 6.75 hours.
So, your answer is 6 hours 45 minutes per day.
2007-08-07 05:00:11 · answer #8 · answered by Joshua B 4 · 1⤊ 0⤋
this usually is a inversely portional qn
i.e more men less hr
if 30 men : 20day
then (30/40)x 20days
the days should be 15 days
2007-08-07 04:59:14 · answer #9 · answered by herbman76 2 · 0⤊ 0⤋
I answer it as
30 men......................(20*9)hours
so, 40 men.........................??? hours
& then determine if u need them to work 9 hours a day
by dividing get the no. of days
2007-08-07 05:03:10 · answer #10 · answered by hfgdsgfggf 2 · 0⤊ 0⤋