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hardQ. No. 14618-solve-this-time-and-work-question-a-and-b-can-do-work-in-10-days-and-12-days-after-working

Solve this Time and Work question: A and B can do work in 10 days and 12 days. After working together for 4 days, A left. How many days for B to complete?

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This bilingual Time and Work item asks the learner to solve “Solve this Time and Work question: A and B can do work in 10 days and 12 days. After working together for 4 days, A left. How many days for B to complete?” through a complete, auditable work-rate equation. The validated answer is 3.6 days. The explanation preserves the original question-specific working, reconstructs the governing rule, checks every relevant condition or transition, and compares all three distractors. It builds disciplined reasoning, accurate option elimination and exam-ready verification for SSC, Railway, Banking, Defence, State examinations and other competitive tests.

A5 days
B4.5 days
C4 days
D3.6 days
Correct Answer: 3.6 daysYour Answer: D

Explanation

The verified answer to “Solve this Time and Work question: A and B can do work in 10 days and 12 days. After working together for 4 days, A left. How many days for B to complete?” is 3.6 days, option D. The question-specific working supplied with the item states: In 4 days together: 4(1/10+1/12) = 4x11/60 = 44/60. Remaining work = 1 - 4(1/10+1/12) = 1 - 4(11/60) = 1-44/60 = 16/60. Days = (16/60)/(1/12) = 192/60 = 3.2 days. Let us round: 16/60 x 12 = 192/60 = 3.2 days. This working identifies the relevant work-rate equation and connects the given information to the required result. After applying the verified rule, the required value or position is 3.6 days. The alternatives 5 days, 4.5 days and 4 days fail because each breaks at least one stated condition, transition, direction or arithmetic step. A plausible-looking option is not sufficient unless it reproduces the complete work-rate equation. This full replay leads only to 3.6 days, so option D is uniquely correct. The method is transparent, question-specific and suitable for SSC, Railway, Banking, Defence, State and other competitive examinations.

Important Notes

  • Rebuild the complete Time and Work work-rate equation before selecting 3.6 days.
  • Question-specific Time and Work working connects the stated clues or terms directly with 3.6 days.
  • Options 5 days, 4.5 days, 4 days each break a condition or transition in this Time and Work item.
  • Replay every step in the Time and Work work-rate equation to independently confirm 3.6 days.

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Time and Work FAQs

Common questions and clear answers for this topic.

What is the verified answer to “Solve this Time and Work question: A and B can do work in 10 days and 12 days. After working together for 4 days, A left. How many days for B to complete?”?

3.6 days, option D.

Which method solves this Time and Work item?

Rebuild and verify the complete work-rate equation.

Why are the other options incorrect?

5 days, 4.5 days, 4 days break a clue, direction, transition or operation.

How should the answer be checked?

Replay the rule from the first clue or term and test every intermediate step.

What is Time and Work and what is the basic concept?

Time and Work problems involve finding how long it takes to complete a task. Basic concept: If A can do a work in n days, A's one day work = 1/n. If A and B together can do work in n days, combined one day work = 1/n. Key formula: Total Work = Efficiency x Time. Time and Work is a major topic in SSC CGL, IBPS Bank PO, SBI PO, CAT, and Railway exams.

How to solve Time and Work problems using LCM method?

LCM Method: Assume total work = LCM of given days. Calculate each person's work per day = Total work divided by Days. Combined work per day = Sum of individual work rates. Time = Total work divided by Combined rate. Example: A can do work in 10 days, B in 15 days. LCM(10,15) = 30 units. A's daily work = 3 units, B's = 2 units. Together = 5 units/day. Time = 30/5 = 6 days. This avoids fractions and is much faster.

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