rajz_123

 Profile Answers by rajz_123 

• Nov 28th, 2005

 

QUESTION OF THIS KIND CAN BE SOLVED USING A FORMULA OF TIME AND WORK.

THE FORMULA IS:

(M1*D1*H1*E1)/W1=(M2*D2*H2*E2)/W2

WHERE M(i)=number of men

D(i)=number of days to complete the work

H(i)=number of hours

E(i)=efficiency

W(i)=work that is being done

THEREFORE THE ANSWER FOR THIS QUESTION IS 71/2 HRS

rahuljain000

 Profile Answers by rahuljain000 

• Jan 8th, 2008

 

answer given in option is incorrect

jayanand

 Profile Answers by jayanand 

• May 6th, 2008

 

1 mans one day work=1/30*20*9
30 mans------=1/20*9
40 mans------=1/40*20*x
so as man increases no of hours decreases i.e. invers proportion

so 30*9=k
so 40*h=30*9
h=30*9/40=27/4:=7 hrs

Purushottam Rathore

• Jul 13th, 2017

 

How it is possible 27/4=7 hours. I have seen this answer some people give 7 hour and 15 minutes, 7 1/2 hrs,
x=6 3/4 hrs answer but the right answer is 6.75 hours.
Solutions:
30 * 20 * 9 = 5400 man-hours required to complete the job
Let x = no. hrs a day to do the same job (assuming in 20 days)
40 * 20 * x = 5400
800x = 5400
x = 5400%2F800
x = 6.75 hrs a day for 20 days to do the same job

Mustapha

• Jun 21st, 2018

 

In the 20 days, the 30 men would have worked for a total of 20*30*9 = 5400 hours.
I.e 5400 man-hours per 20 days
40 men * x hr/day = 5400 man- hours / 20 days
x = 5400/(20*40) = 6.75 hours/day

Anshuman

• Sep 14th, 2020

 

30*9*20=40*20*x
x=30*9*20/40*20
so x=27/4=6.75(ans)