Carcass wrote:
A team of 6 workers is building a levee. If each man works at the same rate and it takes 1 man 18 hours to build a levee, how long would it take the team to build a levee?
A. 3
B. 6
C. 9
D. 27
E. 54
APPROACH #1:
In general, if it takes 1 man k hours to complete a job, then:
- it will take 2 men HALF the time (i.e., k/2 hours) to complete the job
- it will take 3 men ONE-THIRD the time (i.e., k/3 hours) to complete the job
- it will take 4 men ONE-FOURTH the time (i.e., k/4 hours) to complete the job
- it will take 5 men ONE-FIFTH the time (i.e., k/5 hours) to complete the job
- it will take 6 men ONE-SIXTH the time (i.e., k/6 hours) to complete the job
We're told that it takes 1 man 18 hours to complete the job.
So, it will take 6 men 18/6 hours to complete the job
18/6 = 3 hours
Answer: A
APPROACH #2:
Another approach is to assign a NICE VALUE to the job.
Given: 1 man 18 hours to build a leveeSo, let's say that building a levee requires the placement of
18 bricks (this number works well with the given information).
This means
ONE MAN can place
1 brick per hour
So,
SIX MEN can place a total of
6 bricks per hour
The ENTIRE JOB requires placement of
18 bricks
Time = output/rate =
18/
6 = 3 hours
Answer: A
_________________
Brent Hanneson - founder of Greenlight Test Prep