Roshar has 50 minutes/hour, 20 hours/day, 5 days/week, 10 weeks/month (50-day months), 10 months/year (500-day years). Brandon and Peter have said that a Rosharan year is 1.10 Earth years and that a Rosharan hour is shorter than an Earth hour. (This suggests we should assume the 1.10 number is precise.)
The definition of years and days on Earth is ambiguous. With no seasons, the Rosharan year is determined according to the stars, so we'll assume Rosharan year refers to the sidereal year. An Earth sidereal year is 365.25636 SI days of exactly 24 SI hours. So for Earth we'll use 60 minutes/hour, 24 hours/day, 7 days/week, 30 days/month, and 365.25636 days/year.
Using R to represent Roshar and E to represent Earth:
1 R minute = 1.16 E minutes = 69.4 E seconds
1 R hour = 0.964 E hours = 57.9 E minutes
1 R day = 0.804 E days = 19.3 E hours
1 R week = 0.574 E weeks = 4.02 E days
1 R month = 1.34 E months = 40.2 E days
1 R year = 1.10 E years = 13.4 E months = 402 E days
A 10 year-old Rosharan is 11 in Earth years.
A 20 year-old Rosharan is 22 in Earth years.
A 80 year-old Rosharan is 88 in Earth years.