John and Ling start their new jobs on the same day. John's schedule is 4 workdays followed by 1 day off. Ling's schedule is 7 workdays followed by 2 days off. On how many days during their first year of work (365 days) do John and Ling have the same day off?
John's day off is every 5th day. Ling's day off is every 8th and 9th day. LCM(5, 8) =40 and 365/40 =~ 9 times per year LCM(5, 9) =45 and 365/45 =~ 8 times per year. 9 + 8 =~17 times per year.
