A is twice as good a workman as B and together they finish a piece of work in 18 days.in how many days will A alone finish this work?
Lets suppose that worker A works finishes a job in A days
and worker B finishes a job in B days
Then worker A's rate is
Then worker B's rate is
But we know that worker A is "twice" as good (2 times as fast) as worker B
so
We can now set the rates equal
Plugging in and solving for A gives A=27.
I hope this helps