Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 10 Answered

A group of men decided to do a job in 8 days. But since 10 men dropped out after 1st day, 2 more men dropped out after 2nd day, 2 more men dropped out after 3rd day and so on, the job got completed at the end of 12th day. How many men were there at the beginning?

 

55

 

 

56

 

 

57

 

 

58

Asked by 105236 | 31 Aug, 2021, 06:26: PM
Expert Answer
Let x men in group . If work is to be completed in 8 days , then number of man-days = 8x
 
Man-days in each day is tabulated below 
 
day 1 2 3 4 5 6 7 8 9 10 11 12
Man-day x x-10 x-12 x-14 x-16 x-18 x-20 x-22 x-24 x-26 x-28 x-30
 
sum of man-days , 8x = x +(x-10) + (x-12) + (x-14) + (x-16) + (x-18) + (x-20) + (x-22) + (x-24) + (x-26) + (x-28) +(x-30)
 
8x = 12 x  - ( 10 + 12+ 14 ...................... +28+30 )
 
8x = 12 x - [ (11/2) ( 10 + 30 ) ] = 12 x - 220 
 
From above expression, we get , x = 55 
 
Hence , there were initially 55 men in the group
 

Answered by Thiyagarajan K | 16 Sep, 2021, 11:37: PM
CBSE 10 - Maths
Asked by apal63216 | 02 Jan, 2021, 07:40: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by arindeep.singh | 10 Jul, 2020, 06:33: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by pushpa.Kudle09 | 12 Mar, 2020, 12:37: AM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by dastirthankar13 | 10 Mar, 2020, 08:22: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by drhimasingh | 26 Dec, 2019, 06:14: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by hemapooja7890 | 21 Nov, 2019, 10:45: PM
ANSWERED BY EXPERT
×