Question

A,B and C together can do a piece of work in 15 days . B alone can do it in 30 days and C alone can do it in 40 days . In now many days will A alone can do the work

Answer 1

A, B and C together can do a piece of work  = 15 days

One day work of A,B and C                             = 1/15

B alone can do a piece of work                      = 30 days

One day work of B                                           = 1/30

C alone can do a piece of work                     =  40 days

One day work of C                                          =  1/40

One day work of A                                          =  [1/15-(1/30+1/40)]

                                                                        =  1/120

A alone can do a piece of work                     =  120 days