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A can complete a work in x days and B can complete the same work in 15 days. Find out how many days will they take together to complete the work if A is 75% efficient of B.1. 152. 20/33. 60/74. 13 |
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Answer» Correct Answer - Option 3 : 60/7 Given : A can do a work in ‘x’ days B can do the work in 15 days The efficiency of ‘A’ is 75% of the efficiency of ‘B’ Concept used : The efficiency of a person × Number of days he took to complete the work = Total Work Number of days to complete the work = Total work/Work done every day Calculations: Let the working efficiency of B be ‘b’ Let the working efficiency of A be ‘a’ Work for A = Work for B The efficiency of A × x = Efficiency of B × 15 ⇒ a × x = b × 15 ⇒ 75% of b × x = b × 15 ⇒ (3/4) b × x = b × 15 ⇒ x = 20 days Now, total work = LCM of 20 and 15 = 60 units A’s per day work = (Total work/Total days he took) = 60/20 ⇒ 3 units B’s per day work = 60/15 ⇒ 4 units A and B total work for everyday = 4 + 3 = 7 units Total number of days taken by them = Total work/work done by them every day ⇒ 60/7 ∴ They both will complete the work in 60/7 days |
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