How many hours you should study everyday?

Ashish studies for 4 hours,5 hours and 3 hours respectively on three consecutive days. How many hours does he study daily on an average?

Working 8 hours a day, Ashu can a book in 18 days. How many hours a day should he work so as to finish the work in 12 days?

Fifteen men take 10 days to complete a job working 12hours a day. How many hours in a day should 10 men work to complete the same job in 20 days?

Working 10 hours a day, Aman can complete a piece of work in 18 days. How many hours a day should he work so as to finish the work in 15 days ?

Fifteen men take 10 days to complete a job working 12 hours a day.How many hours a day should 10 men work to complete the job in 20 days ?