Practice Questions
Concept Explanation
Work equivalence uses the relation: more workers finish in fewer days when work stays the same.
Key Formulas
- M1 × D1 = M2 × D2 (same work, same hours per day)
- M1 × D1 × H1 = M2 × D2 × H2
- Total work = Men × Days × Hours per day
Example
5 men finish in 12 days. Work = 60 man-days. 8 men need 60/8 = 7.5 days.
Common Trap
Keep units consistent: convert hours or workers before applying M1D1 = M2D2.
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Q1 Easy
If 5 men can finish the work in 12 days, in how many days can 8 men finish the same work?
ExplanationTotal work = 60 man-days. Time for 8 men = 60/8 = 7.5 days. -
Q2 Easy
If 6 workers can finish the work in 10 days, in how many days can 4 workers finish the same work?
ExplanationTotal work = 60 worker-days. Time for 4 workers = 15 days. -
Q3 Medium
If 8 men can finish a work in 9 days, in how many days can 6 men finish the same work?
ExplanationTotal work = 72 man-days. Time for 6 men = 12 days. -
Q4 Medium
If 10 men can finish a work in 6 days, how many men are needed to finish the same work in 4 days?
ExplanationTotal work = 60 man-days. Required men = 60/4 = 15. -
Q5 Hard
If 4 men working 9 hours a day can finish a work in 10 days, in how many days can 6 men working 6 hours a day finish the same work?
ExplanationTotal work = 4 × 9 × 10 = 360 man-hours. Time = 360/(6 × 6) = 10 days. -
Q6 Easy
If 12 men can finish a work in 5 days, in how many days can 10 men finish the same work?
ExplanationTotal work = 60 man-days. Time for 10 men = 6 days. -
Q7 Easy
If 7 men can finish a work in 8 days, in how many days can 14 men finish the same work?
ExplanationTotal work = 56 man-days. Time for 14 men = 4 days.
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Q8 Medium
If 5 men can finish a work in 16 days, in how many days can 8 men finish the same work?
ExplanationTotal work = 80 man-days. Time for 8 men = 10 days. -
Q9 Medium
If 9 workers can finish the work in 12 days, in how many days can 6 workers finish the same work?
ExplanationTotal work = 108 worker-days. Time for 6 workers = 18 days. -
Q10 Easy
If 3 men can finish a work in 20 days, in how many days can 5 men finish the same work?
ExplanationTotal work = 60 man-days. Time for 5 men = 12 days. -
Q11 Hard
If 8 men working 5 hours a day can finish a work in 6 days, in how many days can 6 men working 8 hours a day finish the same work?
ExplanationTotal work = 8 × 5 × 6 = 240 man-hours. Time = 240/(6 × 8) = 5 days. -
Q12 Easy
If 15 men can finish a work in 4 days, in how many days can 12 men finish the same work?
ExplanationTotal work = 60 man-days. Time for 12 men = 5 days. -
Q13 Medium
If 6 men can finish a work in 14 days, in how many days can 21 men finish the same work?
ExplanationTotal work = 84 man-days. Time for 21 men = 4 days. -
Q14 Easy
If 10 men can finish a work in 8 days, in how many days can 16 men finish the same work?
ExplanationTotal work = 80 man-days. Time for 16 men = 5 days.
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DS1 Easy
In how many days can 8 men finish the work?
Statement I5 men can finish the work in 12 days.
Statement IIThe amount of work remains unchanged.
ExplanationStatement I alone gives total work = 60 man-days, so 8 men need 7.5 days. -
DS2 Medium
How many workers are needed to finish the work?
Statement I6 workers can finish the work in 10 days.
Statement IIThe work must be finished in 4 days.
ExplanationTotal work = 60 worker-days. Required workers = 60/4 = 15.
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DS3 Easy
In how many days can 6 men finish the work?
Statement I8 men can finish the work in 9 days.
Statement IIThe amount of work remains unchanged.
ExplanationTotal work = 72 man-days. Time for 6 men = 12 days. -
DS4 Medium
Can the work be finished in less than 8 days?
Statement I10 men can finish the work in 6 days.
Statement II12 men are deployed on the same work.
ExplanationBoth statements are needed: total work = 60 man-days and 12 men need 5 days, which is less than 8.