Aptitude - Chain Rule - Discussion

Discussion :: Chain Rule - General Questions (Q.No.15)

15. 

4 mat-weavers can weave 4 mats in 4 days. At the same rate, how many mats would be woven by 8 mat-weavers in 8 days?

[A]. 4
[B]. 8
[C]. 12
[D]. 16

Answer: Option D

Explanation:

Let the required number of bottles be x.

More weavers, More mats (Direct Proportion)

More days, More mats (Direct Proportion)

Wavers 4 : 8 :: 4 : x
Days 4 : 8

4 x 4 x x = 8 x 8 x 4

x = (8 x 8 x 4)
(4 x 4)

x = 16.


Neha said: (Aug 27, 2011)  
Give the explanation fully.

Amitha said: (Sep 6, 2011)  
Please give a clear solution.

No.7 said: (Sep 16, 2011)  
P M D
4 4 4
8 x 8.if ..

x = 8*8*4/4*4
= 16
see...if no. of mats inc. then no. days also inc.(DIRECT)
and if no. of people inc. then no. of days also inc.(DIRECT)

Viraj Kamat said: (Nov 3, 2011)  
Consider this
4 mats in 4 days by 4 people
Therefore each person weaves 1 mat in 4 days

If there are 8 mat weavers and 8 days, each mat weaver can weave 2 mats in 8 days (1mat/4 days)

Since there are 8 mat weavers : 8weavers * 2 mats = 16 mats !

M.V.Krishna/Palvoncha said: (Jan 12, 2012)  
(IN 4 DAYS)

4 WEAVERS CAN WEAVE 4 MATS

=>(1 WEAVER-1 MAT)--------(A)

FROM (A): 8 WEAVERS-8 MATS

SO 8 WEAVERS CAN WEAVE 8 MATS IN 4 DAYS.

IF DAYS ARE DOUBLE, MATS WILL ALSO DOUBLE.(SINCE SAME RATE OF WORK AND NO CHANE IN WEAVERS)

=>8 WEAVERS CAN WEAVE 16 MATS IN 8 DAYS.

Moses said: (Apr 1, 2015)  
4 weavers can weave 4 mats in 4 days.

In one day one weaver weaves 1/4 of a mart at the same rate.

Then 8 weavers weave 1/4 x 8 = 2 mats in one day.

There fore in 8 days 8 weavers weave 8 x 2 =16 mats.

M S Husain said: (Aug 29, 2015)  
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.

Prasanna said: (Nov 3, 2015)  
4 mate weavers 4 days 4 mate. Which simply tells us that 4 mate weavers can make 1 mate/day. If mate weavers are 8 then 2 mates per day. So for 8 days 16 mats.

Manasa said: (Dec 28, 2015)  
I'm confused about direct and indirect. Please help how to see?

Kriti said: (Jun 19, 2016)  
If 4 are weaving 4 mats in 4 days means 1 mat by 1 person then why not 8 men are weaving 8 mats in 8 days.

Xyz said: (Sep 1, 2016)  
How it is solved? Please explain properly.

Karthik said: (Sep 8, 2016)  
@XYZ
Let's split the problem into 2 sides.

* Mates per day.
* Persons Per mate per day.

In Problem it clearly states that 4 mates per 4 days.

4 mates --> 4 day.
1 mate ----> 4/4 = 1.

So 4 mate weavers 1-day job = 1 mate.
8 mate weavers 1-day job = 1* 8/4 = 2 Mates.
8 mate weavers 2-day job = 2 * 8 = 16.

Sangeetha said: (Apr 22, 2017)  
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.

Magnesh said: (Aug 31, 2017)  
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.

Mp said: (Aug 31, 2017)  
@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.

Sushi said: (Mar 10, 2019)  
@Viraj Kamat.

Thank You.

Minte said: (Aug 17, 2020)  
@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.

Mani said: (Aug 22, 2020)  
Can any tell me, how to solve this by using direct and indirect proportions?

Ponnu said: (May 29, 2021)  
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.

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