Solve for Time: 3 Workers vs 4 Workers Painting Rate Problem

Question

3 workers finish painting a room in 4 hours.
How many hours will it take 4 workers to paint the same room?

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Calculate the work rate for the 3 workers.
  • Step 2: Determine the equivalent rate when 4 workers are involved.
  • Step 3: Calculate the time required for 4 workers using the combined rate.

Let's go through each step in detail:

Step 1: Calculate the work rate for the 3 workers.
If 3 workers can complete the task in 4 hours, then their combined work rate is:

Rate of 3 workers=1 room4 hours \text{Rate of 3 workers} = \frac{1 \text{ room}}{4 \text{ hours}}

Therefore, the rate of 1 worker is:

Rate of 1 worker=13×1 room4 hours=112 rooms per hour \text{Rate of 1 worker} = \frac{1}{3} \times \frac{1 \text{ room}}{4 \text{ hours}} = \frac{1}{12} \text{ rooms per hour}

Step 2: Determine the equivalent rate when 4 workers are involved.
If each worker has a rate of 112 rooms per hour \frac{1}{12} \text{ rooms per hour} , then 4 workers would have a combined rate of:

Rate of 4 workers=4×112 rooms per hour=412 rooms per hour=13 rooms per hour \text{Rate of 4 workers} = 4 \times \frac{1}{12} \text{ rooms per hour} = \frac{4}{12} \text{ rooms per hour} = \frac{1}{3} \text{ rooms per hour}

Step 3: Calculate the time required for 4 workers using the combined rate.
To complete 1 room, the time required by 4 workers is:

Time=WorkRate=1 room13 rooms per hour=3 hours \text{Time} = \frac{\text{Work}}{\text{Rate}} = \frac{1 \text{ room}}{\frac{1}{3} \text{ rooms per hour}} = 3 \text{ hours}

Therefore, the solution to the problem is 3 hours.

Answer

3 hours