60 man can do a work in 40 days. How long will it take 40 men to complete the same work?

60 man can do a work in 40 days. How long will it take 40 men to complete the same work?

Explanation

Men days

60 : 40

40 : x           

60/40= x/40,     40x= 60* 40

x= 40*60/40,      x= 60