U r a genius if u solve this problem.
I wanted the ans. thats why i posted it in yahoo answers:
Its a simultaneous equation
Question:
3 men and 4 boys can do a piece of work in 14 days, while 4 men and 6 boys do the same work in 10 days. How long would it take ONE man to finish the same work ?
I tried my best to solve it, lets see what is your best....
2006-11-18 04:33:49 · 9 answers · asked by grandmaster_u_lost_this 1 in Science & Mathematics ➔ Mathematics
let m = the amount of work 1 man can complete in1 day, let b = the amount of work one boy can do in a day.
42m + 56b = 1
40m + 60b = 1
1680m + 2240b = 40
1680m + 2520b = 42
280b = 2
b = 1/140.
42m + 2/5=1 [56/140=2/5]
42m = 3/5
m = 1/70.
So one man can do 1/70 of the job in 1 day, so it takes him 70 days to do the whole job.
So the answer is 70 days.
Also, my answer is correct, not 22 as many people are saying. If it were 22, then 3 men could complete the job alone in just 7 1/3 days. But even working with 4 boys it takes them 14!
2006-11-18 05:00:05 · answer #1 · answered by Texas Cowgirl 3 · 1⤊ 0⤋
4
2006-11-18 12:41:09 · answer #2 · answered by ayok 2 · 0⤊ 0⤋
I like this m/b business. Thus the total produce p=(u*m1+v*b1)*t1=(u*m2+v*b2)*t2, where t1=14days, t2=10days, m1=3men, m2=4men, b1=4boys, b2=6boys, while u is man work productivity & v is boy work productivity per 1 day. Plug numbers in: u*3*14+v*4*14=u*4*10+v*6*10 or 2u=4v or u=2v,
Thus 2 boys worth 1 man. Thus p=(4u+6v)*10=70u is work for 70 men days, that is 70 days for one man. hard job for him!
2006-11-18 15:11:27 · answer #3 · answered by Anonymous · 0⤊ 0⤋
the answer is 6days because if you look there is 3men and 4boys and they do work in 14days and then there is 4men and 6boy and they do work in 10days, there is a pattern 14-4=10 then you do 10-4 again.and that = 6 so hope is right answer and glad to help
2006-11-18 12:40:18 · answer #4 · answered by izziekittycutie929 2 · 0⤊ 0⤋
that's easy...you simply make a system 3m+4b=14 and 4m+6b=10 and resolve it and the answer is that one man can do it in 22 days
2006-11-18 13:02:20 · answer #5 · answered by elis 2 · 0⤊ 0⤋
not sure if this is right or wrong but
3m+4b=14
4m+6b=10
add them
7m+10b=24
solve for b
-4(3m+4b)=14
3(4m+6b)=10
-12m-16b= -56
12m+18b= 30
add them
2b= -26
b= -13
sub -13 for b in equation 7m+10b=24
7m+10(-13)=24
7m-130=24
7m=154
m=22 days
2006-11-18 12:58:28 · answer #6 · answered by 7 · 0⤊ 0⤋
i think one man can do the same work in 22 days.iam not sure,just a mental calculation.
2006-11-18 12:43:20 · answer #7 · answered by remya 1 · 0⤊ 0⤋
I also got. It will take a one man 22days to do a piece of work.
2006-11-18 14:44:36 · answer #8 · answered by .margarita. 2 · 0⤊ 0⤋
3x+4y=14
4x+6y=10
x=22 days i think
2006-11-18 12:56:36 · answer #9 · answered by tamana 3 · 0⤊ 0⤋