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A is 50% more efficient than B and so finishes the work 15 hours before B finishes the same work. Find the time taken by A (in hours) to finish double the work.1. 30 hours2. 40 hours3. 50 hours4. 60 hours5. 80 hours |
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Answer» Correct Answer - Option 4 : 60 hours Given: A is 50% more efficient than B. Time is taken by A to finish the work = time taken by B – 15 Concept used: Work = time × efficiency When work done by A and B is the same, t ∝ 1/e; where ‘t’ is time and ‘e’ is efficiency. Calculation: The ratio of efficiency of A to B = 3 ∶ 2 The ratio of time of A to B = 2 ∶ 3 Then, time is taken by A to finish the task = time taken by B – 15 ⇒ 2x = 3x – 15 ⇒ x = 15 Time taken by A to finish work = 2x = 30 hrs Then, time is taken by A to do double the work = 2 × 30 = 60 hours. ∴ Time is taken by A to finish double the work is 60 hours. |
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