1. ## Inverse

If it takes 9 people to collect 10 kg of wood in 12 hours. How long does it take 7 people to collect 7.5 kg of same wood?

2. ## Re: Inverse

Originally Posted by joshuaa
If it takes 9 people to collect 10 kg of wood in 12 hours. How long does it take 7 people to collect 7.5 kg of same wood?

one person collects (10/9) kg wood in 12 hrs ...

3. ## Re: Inverse

so in the second side one person collects 7.5/7 in unknown hours. I still need to know the time???

4. ## Re: Inverse

(number of people)(wood collection rate for 1 person)(time) = total wood collected

5. ## Re: Inverse

If we plug the values of the left side
(9)(10/9)(12) = 10
120 = 10 is the final answer which is not correct

If we plug the values of the right side
(7)(7.5/7)(X) = 7.5
X = 1 is the final answer which I think is not correct too

Explain More...

6. ## Re: Inverse

Originally Posted by skeeter
(number of people)(wood collection rate for 1 person)(time) = total wood collected
one more time ...

$(9 \, people) \cdot \left(\frac{(10/9) \, kg}{12 \, hrs}\right) \cdot (12 \, hrs) = 10 \, kg$

now do it for 7 people and and 7.5 kg and solve for t

7. ## Re: Inverse

(7)[(7.5/7)kg/t](t) = 7.5
i end up with 7.5=7.5 because t and t was cancelled

8. ## Re: Inverse

$(7 \, people) \cdot \left(\frac{(10/9) \, kg/person}{12 \, hrs}\right) \cdot (t \, hrs) = 7.5 \, kg$

solve for t

9. ## Re: Inverse

Thanks a lot. It was so helpful

10. ## Re: Inverse

Why the rate was not [(7.5/7)/X]?