Question

if it takes 12 people 8 hours to do a certain job, how many hours would it take 3 people to do 1/4 of the same job?

Answer 1

8 hours

Answer 2

find how long it takes 3 people to do the whole job
then divide that by 4

Answer 3

@cwrw238 If Julian is correct, you would need to multiply by 4 instead of dividing.

Answer 4

for whole job time by 3 people = 12 * 8
----- = 32 hours
3
- now divide that by 4...

Answer 5

But why not 12/8=3/x as a proportion?

Answer 6

no - the number of hours for 3 people must take more time than when 12 people do it ( time 4)

Answer 7

I see.

Answer 8

this is inverse proportionality

less people - more hours

Answer 9

h = k/p
when h = 8, p = 12
8 = k/12
k = 96

so h = 96/p

when p = 3
h = 96/3 = 32