can any1 solve this for me pplzz?

Question

4 men and 4 boys can do a piece of work in 3 days, while 2 men and 5 boys can finish it in 4 days. how ling would it take 1 boy to do it? How long would it take 1 man to do it?

i am a little confused, u should solve it using linear equations in two variables. and i wrote
let the no. of boys be y and the no of men be x then
1/4x+1/4y=3
1/2x+1/5y=4
but then the answer is a fraction and humans cant be fractions!!!

pl help guys i'll gv 5stars to the correct answer....

Answer 1

Its a rates question.

Let a be the rate at which a man works.
Let b be the rate at which a boy works.
(in # of pieces of work per day)

4a + 4b = 1/3
2a + 5b = 1/4

Solving simulataneously gives:
a = 1/18
b = 1/36

Therefore:
It would take a boy 36 days to do the piece of work and it would take a man 18 days.

Answer 2

here's the thing... you're not counting fractional people... you're counting fractional days!

so, I think you just slid the fraction in on the wrong side of the equation to start.

we want to say:

(4men + 4boys) * 3days = 1 project
12mandays + 12boydays = 1 project

so for just one day, we divide by the 3 day total, and get:

4man + 4boy = 1/3 project per day

figure out what one man is worth:

4man = 1/3 - 4boy

man = 1/12 - boy


then get the next equation:

(2men + 5boys) * 4days = 1 project
8mandays + 20boydays = 1 project

so for just one day, we divide by the 4 day total, and get:

2man + 5boy = 1/4 project per day

Now, we know what a man is worth, so we substitute that in:

2 * (1/12 - boy) + 5 boy = 1/4

2/12 - 2boy + 5boy = 1/4
3boy = 1/4 - 2/12

boy = 1/12 - 2/36 => boy = 3/36 - 2/36

boy = 1/36 project per day!

if a man is 1/12 - boy, then a man is 1/12 - 1/36, or 2/36 (which is also 1/18)

so, a boy can do 1/36th of a project in one day, and a man can do 1/18th of a project in one day.

36 days for the whole project for a boy,
and only 18 days for a man.

Answer 3

1/4x + 1/4y = 3 -------(1) where x = number of days for men
1/2x + 1/5y = 4 -------(2) y = number of days for boys
from equation (1), multiplying through by 4, we have;
x + y = 12 and multiplying through by 10 in equation (2), we have 5x + 2y = 40.
let x + y = 12 be equation (3), solving the problem simultaneously, we have;

5(12 - y) + 2y = 40;
60 - 5y + 2y = 40;
60 - 40 = 3y;
20 = 3y;
therefore, y = 20/3 days,

from equation (3);
x = 12 - 20 / 3
= (36 - 20) / 3
= 16 / 3 days.

hence, it takes a man 16 / 3 days and a boy 20 / 3 days to finish the same job.

Note that it is days not number of men. days can be fraction but it cant be negative. And always subject your answer to logical test. Take for instance, is the answer logical? u answer that yourself. if you cant, read the question again and make sure you understand it well.

Answer 4

is the answer 8 days ? And by the way read ur sentence, u sed "the answer u are getting is in fraction and humans cant be in fractions", but days can. Your question was how long will 1 man and boy take to complete da task. Hw long - as in days not humans. So, u might be right.

Answer 5

1/(4m + 4b) = 3
1/(2m + 5b) = 4
12m + 12b = 1
8m + 20b = 1
24m + 24b = 2
24m + 60b = 3
36b = 1
b = 1job/36 days
12m + 12/36 = 1
12m + 1/3 = 1
36m = 3 - 1
m = 1 job/18 days

Answer 6

4a+4b=1/3
2a+5b=1/4


Solving the equations gives a=18,b=36

Answer 7

if they hired a JCB excavator 1 person could do the job in 20 mins letting the boys go to school

Answer 8

I pity the poor candle.It only enables others for all time and each time it enables,previous age creeps up and on the top she's no longer something yet melted wax.Boooohooooo.How unhappy.yet i do no longer think of a candle can help the blind.Blind human beings won't be able to see something.

Answer 9

Get a couple of Mexicans and get it done in a day for HALF the cost.

Answer 10

uhhh i donno