A, B and C together can build a wall in 12 days. C is four times as productive as B and A alone can build the wall in 48 days. In how many days A and B working together can build the wall?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 30
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Understanding |
Application |
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A, B and C together can build a wall in 12 days. C is four times as productive as B and A alone can build the wall in 48 days. |
Suppose total units of work = 48 units (LCM of 12 and 48) So, Efficiency of A = 48/48 = 1 Efficiency of (A + B + C) = 48/12 = 4 So, Efficiency of (B + C) = 4 – 1 = 3 And Efficiency of C = 4 × Efficiency of B Suppose efficiency of B = x So, x + 4x = 3 x = 0.6 Hence, Efficiency of B = 0.6 Hence, Number of days A and B working together can build the wall = 48/(1 + 0.6) = 30 |