## anonymous one year ago Word Problems Help! 12 men take 6 hours to finish a work. After the 12 men have worked for 1 hour, the contractor decides to call in 8 more men so that the work can be completed earlier. How many hrs would 20 men take to complete the remaining work?

1. Hero

2. Hero

@JustinSpeedster you still here?

3. anonymous

work = men/hour $\frac{ 12 }{ 6 }$$\frac{ 12 }{ 6 }\ - \frac{ 1 }{ 5 }$ is that right?

4. anonymous

@Hero sorry for the afk...can you teach me how to solve it? I'm stuck.

5. Hero

The key to solving this Is Keeping track of the total man hours

6. Hero

It takes 12 men 6 hours to complete the Work

7. Hero

multiplying 12 by 6 gets you 72 total man hours necessary to complete the job.

8. Hero

They tell us that the 12 men have already worked 1 hour or 12 man ho urs so We Subtract 12 from 72 to get 60 Man hours remaining

9. Hero

They add eight more men to this project so at that point , we have 20 men and 60 Man hours left to complete the job. How many hours will it take?

10. anonymous

I don't get it T.T

11. anonymous

5 hours?

12. Hero

At this point you divide 60 by 20 to get the number of hours it will take the 20 men to complete the job.

13. anonymous

3 hours

14. Hero

yes three hours, now try to understand the reasoning behind this approach.

15. anonymous

why did you multiply 12 by 6?

16. Hero

To Calculate the total man hours necessary to complete the work.

17. anonymous

OH I see..I guess it was easy after analyzing it. I feel like a stupid now. The conflict that I encountered was the forming of equation. I failed to calculate the man hours....I was focused on solving the rate on how 1 worker/hour to solve everything. Oh well. Thanks for the help, HERO. Another lesson well taught. :D

18. Hero

I don't like solving it using fractions. That approach is slightly unintuitive.

19. Hero

my first train of thought is to calculate total man hours Instead of rate