How to Solve Time and Work — Step by Step Guide

Step-by-Step Method

1. 1

   Find each person's work rate: if A can do a job in n days, A's rate = 1/n per day.

2. 2

   Combined rate: if A and B work together, their combined rate = 1/a + 1/b per day.

3. 3

   Time taken together = 1 / (combined rate).

4. 4

   For partial work: if A works for d₁ days and B for d₂ days, total work = d₁/a + d₂/b.

5. 5

   Work done must equal 1 (the whole job) when the task is complete.

Worked Example

Common Mistakes to Avoid

• ✗

  Adding the number of days directly instead of adding the rates.

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  Confusing rate with time — more workers means less time, not more.

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  Not accounting for one worker leaving partway through the job.

• ✗

  Forgetting that the total work done must equal 1.

Practice Time and Work on SparkEd

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Frequently Asked Questions

How do I solve Time and Work problems?

Find each person's work rate: if A can do a job in n days, A's rate = 1/n per day. Combined rate: if A and B work together, their combined rate = 1/a + 1/b per day.

What are common mistakes in Time and Work?

Adding the number of days directly instead of adding the rates. Confusing rate with time — more workers means less time, not more.

Which class covers Time and Work?

Time and Work is typically taught in Class 7, 8. SparkEd has free practice for all these grades.

Where can I practise Time and Work for free?

SparkEd offers free chapter-wise practice for Time and Work aligned to CBSE, ICSE, and IB curricula. Visit sparkedmaths.com to start.