Three workers can do a job in 28 hours. How many more workers are needed to do this job in 12 hours?
It’s not 7
It is 4 workers
To solve this problem, we need to determine how the number of workers affects the time it takes to complete the job. Let's break down the given information:
- We know that three workers can complete the job in 28 hours.
- We want to find out how many more workers are needed to complete the job in 12 hours.
First, let's find the total work required for the job. Since it takes three workers 28 hours to complete the job, we can set up the proportion:
3 workers → 28 hours
X workers → 12 hours
To find the total work, we can use the formula:
Total work = Number of workers × Time
For the first scenario with three workers for 28 hours, the total work is:
Total work = 3 workers × 28 hours = 84 worker-hours
Now, let's set up a new proportion to find the number of workers needed for 12 hours:
X workers → 12 hours
Using the total work as a reference, we can set up the following proportion:
3 workers → 28 hours
X workers → 12 hours
Now, we can cross-multiply and solve the equation:
(3 workers) × (12 hours) = (X workers) × (28 hours)
36 worker-hours = 28X worker-hours
Divide both sides by 28 to find X:
X = 36 worker-hours / 28 worker-hours
X ≈ 1.29
Therefore, approximately 1.29 more workers are needed to complete the job in 12 hours. Since we can't have a fraction of a worker, we can conclude that 2 additional workers are needed.
12/28 as much time, so 28/12 as many workers.
28/12 * 3 = 7