Math Problem Statement

The task maker can perform the task in 40 minutes. The apprentice can perform the task in 1 hour. How long will it take both to perform 5 tasks working together if the taskmaster works 1 hour before the apprentice joins in?

Solution

Let's break this down step by step.

Step 1: Taskmaker's rate of work

The taskmaker can perform 1 task in 40 minutes. This means the taskmaker’s rate of work is:

Taskmaker’s rate=1task40minutes=140tasks per minute\text{Taskmaker's rate} = \frac{1 \, \text{task}}{40 \, \text{minutes}} = \frac{1}{40} \, \text{tasks per minute}

Step 2: Apprentice's rate of work

The apprentice can perform 1 task in 1 hour (which is 60 minutes). Therefore, the apprentice's rate of work is:

Apprentice’s rate=1task60minutes=160tasks per minute\text{Apprentice's rate} = \frac{1 \, \text{task}}{60 \, \text{minutes}} = \frac{1}{60} \, \text{tasks per minute}

Step 3: Work done by the taskmaker in the first hour

The taskmaker works alone for 1 hour (which is 60 minutes). During this time, the amount of work completed by the taskmaker is:

Work by taskmaker in 1 hour=Rate of taskmaker×60minutes=140×60=1.5tasks\text{Work by taskmaker in 1 hour} = \text{Rate of taskmaker} \times 60 \, \text{minutes} = \frac{1}{40} \times 60 = 1.5 \, \text{tasks}

So after the first hour, the taskmaker completes 1.5 tasks, leaving 51.5=3.55 - 1.5 = 3.5 tasks still to be completed.

Step 4: Combined work rate of taskmaker and apprentice

Once the apprentice joins, both the taskmaker and the apprentice work together. Their combined rate of work is:

Combined rate=140+160=3120+2120=5120=124tasks per minute\text{Combined rate} = \frac{1}{40} + \frac{1}{60} = \frac{3}{120} + \frac{2}{120} = \frac{5}{120} = \frac{1}{24} \, \text{tasks per minute}

This means they can complete 124\frac{1}{24} tasks per minute working together.

Step 5: Time taken to complete the remaining 3.5 tasks

The remaining work is 3.5 tasks, and their combined rate is 124\frac{1}{24} tasks per minute. Therefore, the time it takes for them to complete the remaining tasks is:

Time=3.5tasks124tasks per minute=3.5×24=84minutes\text{Time} = \frac{3.5 \, \text{tasks}}{\frac{1}{24} \, \text{tasks per minute}} = 3.5 \times 24 = 84 \, \text{minutes}

Step 6: Total time

The total time is the 1 hour (60 minutes) that the taskmaker worked alone, plus the 84 minutes they worked together:

Total time=60minutes+84minutes=144minutes\text{Total time} = 60 \, \text{minutes} + 84 \, \text{minutes} = 144 \, \text{minutes}

Converting this to hours and minutes:

144minutes=2hours and24minutes144 \, \text{minutes} = 2 \, \text{hours and} \, 24 \, \text{minutes}

Final Answer:

It will take 2 hours and 24 minutes for both to perform 5 tasks, with the taskmaker working alone for the first hour.


Would you like more details on this solution? Here are some related questions:

  1. What if the taskmaker worked alone for 30 minutes instead of 1 hour?
  2. How would the solution change if the apprentice could perform 1 task in 50 minutes?
  3. Can we calculate the time if both the taskmaker and apprentice worked the entire time together?
  4. What is the total amount of work completed after both work together for 2 hours?
  5. How would the total time change if they needed to complete 10 tasks instead?

Tip: To find combined rates, always sum individual rates and then divide the remaining work by this combined rate to find the time needed.

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Math Problem Analysis

Mathematical Concepts

Rates of work
Combined work rates
Time calculation

Formulas

Taskmaker's rate = 1/40 tasks per minute
Apprentice's rate = 1/60 tasks per minute
Combined rate = Taskmaker's rate + Apprentice's rate = 1/24 tasks per minute
Time to complete remaining tasks = Remaining tasks / Combined rate

Theorems

Rate of work and time relationship

Suitable Grade Level

Grades 8-10