Probability on Surfing

Question

John spends 2 hours per day on the internet at the weekend. A day is selected randomly from three weeks.

Find the probability John spends 2 hours on the internet on that day.

Answer 1

In 3 weeks, there are 21 days. Each weekend has 2 days, for a total of 6 weekend days in 3 weeks. So the probability of a day being an internet surfing day is 6 / 21, which reduces to 2 / 7.