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A,B & C can do a work in 15 hr, 12hr & 20hr respectively. At 4.00 pm ,they start working together and after working for 2 hr , A left the work and B left 2 hr before the completion of the work. In what time the whole work will be completed ? |
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Answer» Answer: Step-by-step explanation: In such questions we may take LCM of each i.e. 12 and 18 which is 36 We assume as 36 units of work (say some 36 TOYS to be made) is The Complete Work Since A takes 12 hour, he makes 3 units each hour Since B takes 18 hours to prepare 36 units, he makes 2 units each hour Starting with A followed by B, in first 2 hours 5 units made, in next 2 hours, 5 more and so on TILL 35 units in 7X2 =14 hours… A will take 1/3hour to MAKE 36th unit i e. 20 min. So time taken to complete 36 units of work is 14(1/3) hours Or 14 hour 20 minutes So starting from 8 am it will be 8 pm after 12 hours and 10:20 pm after 14hr 20 min. |
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