2007-12-18 15:23:26 · 14 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
First we figure out the man days required.
Your task takes 84 man days to complete at 6 in 14 days (6 x 14). This means it would take 1 man 84 days to do this work or 84 men 1 day.
To calculate other workforce requirements, we simply divide the number of man days required (84) by the number of days we have to get it done (21) and come up with the number of men required for the job (4)
84 ÷ 21 = 4
add: wow, people in math answer really fast. ☺
2007-12-18 15:31:35 · answer #1 · answered by CoachT 7 · 2⤊ 0⤋
6 / x = 14 / 21
6 * 21 / 14 = x
x = 9
9 men
2007-12-18 15:27:23 · answer #2 · answered by ANTHONY V 1 · 0⤊ 3⤋
4
The work represents 6*14 person days or 84 person days.
If you have 21 days to do the work then you only need 4 persons.
4*21 = 84.
2007-12-18 15:31:32 · answer #3 · answered by davster 6 · 2⤊ 0⤋
work = men * days = 6*14 = 84 man days.
If you have 21 days to do it then you only need 4 men.
2007-12-18 15:30:56 · answer #4 · answered by William B 4 · 1⤊ 0⤋
x represents the number men of needed to work in 21 days
6/14 = x/21
126 = 14x
126/14 = 14x/14
9 = x
Therefore, there will be 9 men needed to work in 21 days
2007-12-18 15:33:31 · answer #5 · answered by Vicmar 2 · 0⤊ 1⤋
men : days for the same work is inverse ratio
works is done in 14 days by 6 men then
work will be done in 21 days by 6*14/21 men = 4 men
2007-12-18 15:33:55 · answer #6 · answered by sv 7 · 0⤊ 0⤋
4
2016-03-16 03:05:39 · answer #7 · answered by Anonymous · 0⤊ 0⤋
i second oz's answer.
shaany AND Anthony made the fundamental mistake. it doesn't take more days when you have more men working on the job. (well realistically you may... but that's outside the scope of a math problem.)
which idiot gave oz a thumbs down??? it's the right answer. gosh, i hate idiots..
[Addition]
Wow, quite alarming how many people are getting this question wrong. Including the long ass explanation that concludes the WRONG answer.
This is NOT a direct proportion question, it's an inverse relation. I'm not going to explain, it's already been answered correctly a few times below. It's 4!!
For those who still insist it's 9. You're assuming this is a direct relation. i.e. if it takes 1 man to do a job in 1 day, it would take 2 men to do the job in 2 days!! Can you see how ridiculous that is!!
It's dangerous to incorrectly apply mathematical formulas without understanding the question.
2007-12-18 15:28:56 · answer #8 · answered by Anonymous · 1⤊ 0⤋
9 men.
6/14=3/7 X 3= 9/21
2007-12-18 15:26:18 · answer #9 · answered by ? 4 · 1⤊ 2⤋
Four men. The work takes 6 x 14 "man-days" = 84 man-days / 21 days = 4 men
2007-12-18 15:27:13 · answer #10 · answered by ozperp 4 · 4⤊ 1⤋