Question

arun can do a piece of work in 40 days while bunty can do it in 30 days.in how many days arun and bunty are working togethere?

Answer 1

Arun's 1 day work = 1/40

Bunty's 1 day work = 1/30

Arun + Bunty's 1 day work = 1/40 + 1/30

                                               =  70/1200

                                               =  7/120  
           

Arun and bunty can do it in 120/7 days i.e  17.14 days

Answer 2

let work is x
the work done by Arun in 1 day = x/40
the work done by Bunty in 1 day = x/30
the work they done together in 1 day = x/40+x/30
                                                     =7x/120
hence , the work they done together is 7x/120
the time taken is 17.1 days