Question

60 men can complete a piece of work in 40 days.60 men start the work but
after every 5 days 5 people leave.in how many days will the work be completed?
why you are subtracting days and men ?

Answer 1

(60*40) men complete the work in 1 day

1man's 1 day work is 1/60*40

60 men's 5 day work is 5*(1/40)=1/8

remaining work (1-1/8)=7/8

as 5 men leave

55 men's 1 day work=55*(1/60*40)=11/60*8

now

11/60*8 work done by them 1day

7/8 work done by them [(60*8)/11]*(7/8)=420/11=38.18

so they complete in (38.18+5) days{5 day added bcoz alrdy 5dy work had been done}

43.18 day total work will be completed.