A can do a piece of work in 24 hours while B alone can do it in 16 hours. If A, B and C working together can finish it in 8 hours, in how many hours can C alone finish the work?
Number of hours A required do a piece of work : 24 hours
Number of hours B required do a piece of work : 16 hours
Let number of hours C required to do a piece of work : X hours
Number of hours required by A, B and C together to do a piece of work : 8 hours
Work done by A in one hour: 
Work done by B in one hour: 
Work done by C in one hour: 
Work done by A, B and C together in a one hour : 
Work done by A, B and C together in one hour :  =
 =  =
 =  =
 = 
 =
 = 
⇒ 40X +384 = 48X
⇒ 8X = 384
⇒ X =  = 48 hours
 = 48 hours
 Siraj can do the work 48 hours.
 Siraj can do the work 48 hours.