Aptitude - Chain Rule - Discussion

M=4 M=8,
D=4 D=8,
H=x H=x,
W=4 W=4.

Weavers =4:8
Day's =4:8.

Therefore,
4*4*x = 8*8*4
8*8*4 ÷ 4*4
x= 256 ÷16 = 16.

So, The value if x = 16,
Thanks.

Can any tell me, how to solve this by using direct and indirect proportions?

It's too much simple.

Here let x is a work.

Chain Rule: (M1*D1)/W1 = (M2*D2)/W2.

M-men or workers.
D-Days or Time.
W-Works.

= (4*4)/4 = (8*8)/x.

==> x = 16.

@All.

If A can complete a mat in 4 days.
his 1 day of work is 1/4 so he completes 1/4 of mat in one day.
1/4 +1/4+1/4 +1/4 =1 mat.

How it is solved? Please explain properly.

One person can finish 1 mat in 4 days, which means his mat per day is 1/4. If a person has 8 days then he can 8/4 = 2 mats in 8 days.

There are 8 weavers, 8 * 2 = 16.

@All.

Just think it like this, before 4 people complete 4 mats in 4 days, but with the addition of 4 people now 2 people can complete 2 mats in 1 day.

So multiply the finished mats per day i.e 2 with the total no of days i.e 8 and we get 2* 8 = 16.

@Viraj Kamat.

Thank You.

Usually, we select answer as 8 because 4 4 4 so 8 8 8 actually we are wrong.
4 people 4 mats in 4 days.
so 1 man can do 1 mat in 4 days.

(If you think how 1 man 1mat in 4 days = effort of 4 people to make 1 mat in 1 day
effort of 4 people to make 2 mats in 2day, similarly 4 people 4 mats 4 days as good as saying 1 man should work for 4 days to make 1 mat, because everyday he is putting effort to finish1/4 work of a mat, at the end of 4 days( 1/4+1/4+1/4+1/4= 1 mat ))

Now,
For simplicity keep days constant which is 4 days and people 8.
4 men make 4 mats in 4 days.
8 men make ? mats in 4 days.
Since days are same don't worry and simply cross multiply.
8*4/4= 32/4= 8.

So 8 mats in 4 days 8 mats in 4 days
? mats in 8 days
64 /4 = 16.

4man can do 4 mats in 4 in 4 days.
1men can do 4 mats in 16 days.
1 man can do 1 mats in 4 days.
1 man can do 8 mats in 32 days.
8 man can do 8 mats in 4 days.

So, 4 is my answer please explain me briefly that where have I done the mistake.