Time And Work Ratio Quantitative Aptitude Question and Answer From R.S Aggarwal Book

Question: 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 the work? Time and work quantitative aptitude
Aptitude Question: Answer:
First: A is twice as good workman as B:
A=2B----1
Second data: together they finish work in 18 days

A+B=18 days-----2
Third question: How many days A alone finish the work?
A, B they together work there one day work is =1/18
A+B=1/18
Submit equation 1 into 2
3B=1/18
B=1/(18*3)
B=1/54
A=1/18-1/54
A=(3-1)/54=2/54=1/27
Finally A alone he finish the work in 27 days. Source from R.S Aggarwal Book