Question

if x men can do a job in h days, ow long would y men take to do the same job?

Answer 1

\[A) \frac{ x}{ h }\]
\[B) \frac{ xh}{ y }\]
\[C) \frac{hy }{ x }\]
\[D) \frac{ xy}{ h }\]
\[E) \frac{ x}{y }\]

Answer 2

\[j=\frac{ hy }{ x }?\]

Answer 3

x men can do a job in h days, so 1 man will do the job in h*x days.
How many days would y men take to do the job?

Answer 4

i think its letter C

Answer 5

Explain your reasoning please.

Answer 6

well i used what hero did
and got
\[\frac{ jx }{ y }=h \rightarrow (y)\frac{ jx }{ y }=h \]

Answer 7

oh.....

Answer 8

so its not\[j=\frac{ hy }{ x }\]?

Answer 9

ok

Answer 10

Try to follow this reasoning:

x men can do a job in h days, so 1 man will do the job in h*x days.
(more men=faster, less men=slower).

How many days would y men take to do the job?

Can you figure it out?

Answer 11

not really...

Answer 12

We'll look at it this way:
x men can do a job in h days. The job requires x*h man-days to finish.

How many days would it take y men to do a job requiring x*h man-days?

Answer 13

@ineedhelpnow08 are you still there?

Answer 14

yeah....just thinking

Answer 15

The idea of man-days makes the calculation easy.
A job requiring 30 man-days can be done by 5 men in \(\large \frac{30 man-days}{5 men}=6 days \). Notice how the numbers AND the units cancel.
Similarly, a 30 man-day job can be done by 2 men in 30/2=15 days.

Answer 16

hmmm so like if i use this
\[y \times k=x \times h\]
would it work?

Answer 17

Yes, that's the idea. What do you get?

Answer 18

\[\frac{ xh }{ y }\]

Answer 19

Are you sure?

Answer 20

yeah

Answer 21

i divided y on each side to find k

Answer 22

Great! Just checking...! congrats.

Answer 23

thank you!!!

Answer 24

You're welcome!

Answer 25

life saver :)