Question

if 10 persons can clean 10 floors by 10 mops in 10 days , in how many days can 8 persons clean 8 floors by 8 mops?

Answer 1

\(\large\tt \begin{align*} \color{black}{a.) 12.5\hspace{.33em}\\~\\
b.) 10\hspace{.33em}\\~\\
c.) 8.5\hspace{.33em}\\~\\
d.)8\hspace{.33em}\\~\\}\end{align*}\)

Answer 2

@aum

Answer 3

The one that makes most sense is 8

Answer 4

`x` persons take 10 days to clean `x` floors

it doesn't matter what `x` is

Answer 5

` 10 persons can clean 10 floors by 10 mops in 10 days`

think of it like this :
assign one person to each floor, then `each person` completes cleaning his `one floor` in `10 days`
that means one person takes 10 days to clean one floor

Answer 6

so u mean 8 persons clean 8 floors by 8 mops in 8 days , right ?

Answer 7

`x` persons take 10 days to clean `x` floors

replace `x` by 8

Answer 8

how u concluded that

\(\text{x persons take 10 days to clean x floors}\)

Answer 9

we're given this

`10 persons can clean 10 floors in 10 days`

Answer 10

think of an appartment with 10 floors, assign one person to clean each floor

Answer 11

each person takes 10 days to clean his own floor, yes ?

Answer 12

ok yes

Answer 13

does it matter how many floors the appartment has, as long as you have one person to clean for each floor ?

Answer 14

even if the appartment has 10000 floors, it would take just 10 days to clean it by 10000 men

Answer 15

becaus eeach person would be having only one floor to clean

Answer 16

`x` persons take 10 days to clean `x` floors

so it takes 10 days to clean no matter what the value of x is here

Answer 17

so the answer is \(\large 10\)

Answer 18

yes

Answer 19

what about the \(\huge mops\)

Answer 20

thats irrelevant to the problem

Answer 21

ahhaha

Answer 22

whether they are using mops / vacuum cleaner, it doesn't matter as long as they are able to clean the floor in 10 days ;)

Answer 23

oh i see it was extra thing like \(\dfrac{r}{s}\) in my previous question

Answer 24

yes that information is not needed

Answer 25

that was tricky , thnks!

Answer 26

i found this
http://gyazo.com/8b4ff3d40990e80a998058d5f54d71d7

Answer 27

oh , it says "donot get confused by distractions" lol

Answer 28

i was thinking if they have no mops, then would still the answer would be 10

Answer 29

thats a problem for cleaners, not us haha!

Answer 30

ohk lol

Answer 31

It's also interesting to note that in situations like this, it can not be said with certainty that having more persons and more mops make the job faster (or at least not on a linear scale).

You could imagine having 100 persons trying to clean 1 floor would not make it 100 times faster, and in fact could even make it slower. As they would be in each others way all the time.

That's beyond the scope of this particular question, but i just wanted to note it anyway.

Answer 32

:O haha its familiar xD