Arun and Amit can do a piece of work in 9 days and 12 days respectively. If they work for alternate days and Amit starts the work first, th…

As per the given data,

If they work alternately then work done by Arun & Amit in 2 days = 1/9 + 1/12 = 7/36

Work done in 5 pair of days = 5 × 7/36 = 35/36

∴ They require 5 pair of days i.e, 10 days to complete 35/36 parts of whole work