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Bunuel
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If 17 labourers can dig a ditch 20 m long in 18 days, working 8 hours 21 Jan 2021, 06:00
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95% (hard)

Question Stats:

49% (02:21) correct 51% (02:18) wrong based on 136 sessions

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If 17 labourers can dig a ditch 26 m long in 18 days, working 8 hours a day; how many more labourers should be engaged to dig a similar ditch 39 m long in 6 days, each labourer working 9 hours a day?

(A) 34
(B) 51
(C) 68
(D) 85
(E) 88
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B
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imeanup
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If 17 labourers can dig a ditch 20 m long in 18 days, working 8 hours 24 Jan 2021, 12:36
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Bunuel
If 17 labourers can dig a ditch 20 m long in 18 days, working 8 hours a day; how many more labourers should be engaged to dig a similar ditch 39 m long in 6 days, each labourer working 9 hours a day?

(A) 34
(B) 51 = 17+51=68
(C) 68
(D) 85
(E) 88
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Dear Bunuel, Kindly review this question. The ditch in the first case should be 26 m in order to satisfy the Ans B 51
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If 17 labourers can dig a ditch 20 m long in 18 days, working 8 hours 24 Jan 2021, 12:38
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\(\frac{17*8*18}{26}=\frac{6*9*(x+17)}{39}\)

\(x+17=68\)

\(x=51\)
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If 17 labourers can dig a ditch 20 m long in 18 days, working 8 hours 24 Jan 2021, 12:39
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Bunuel
If 17 labourers can dig a ditch 20 m long in 18 days, working 8 hours a day; how many more labourers should be engaged to dig a similar ditch 39 m long in 6 days, each labourer working 9 hours a day?

(A) 34
(B) 51 = 17+51=68
(C) 68
(D) 85
(E) 88


Dear Bunuel, Kindly review this question. The ditch in the first case should be 26 m in order to satisfy the Ans B 51
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Fixed. Thank you!
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If 17 labourers can dig a ditch 20 m long in 18 days, working 8 hours 17 Nov 2023, 07:20
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Consider this

1) 10 men worked for 110 days to finish a job. So 10*110 men.days for 1 job

2) They stopped on the 55th day (given in the question). So in 55 days what part of the job did they complete?
110 days > 1 Job
55 days > ?

Simple cross multiplication ? = 55/110 = 1/2. Ie Half the job is left

4) On the 60th day 6 new men joined. So total men is now 16 (given in the question). So how many days does it take 16 men to complete one full job? From step 1

10*110 men.days / 16 men = (10*110)/16 days to do 1 job

5) But we already know 1/2 the job has been completed (step 3). So for the remain 1/2 16 men will take ((10*110)/16)/2 = ~34.4days

6) so considering they started on the 60 day, without rain they would have finished on the 60+34.4 94.4 ie 95th day. But since they finished on the 100 days, it rained for 5 days
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