Question

A and B can do a piece of work in 30 days B and C can do it in 24 days while C and A in 20 days .they all work together for 12 days when B and C leave .how many days more will A take to finish the work .please tell me in detailed

Answer 1

Answer:

Step-by-step explanation:

(A+B)'s one day's work = 1/30

 

(B+C)'s one day's work = 1/24  ------------(1)

(C+A)'s one day's work = 1/20

∴ (A+B+C)'s one day's work = 1/2 [1/30 + 1/24 + 1/20] = 1/2 [20 + 25 + 30/600]

= 75/1200 = 1/16   -------------(2)

(A+B+C)'s 12 day's work = 12/16 = 6/8 = 3/4  

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Remaining work,  1 − 3/4 = 1/4   (which is done by A)

From (1) and (2), A's one day's work = 1/16 - 1/24 = 1/48  

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∴  Remaining   1/4 of the work is done by A alone in   1/4 × 48 = 12 days.