Question

John likes to hike during the summer he can usually hike about 3 miles every hour but when it's really hot he swims in a mountain lakes for a half hour after every 4 miles how long does it take him to hike 9 miles

Answer 1

During the 9 mile hike he  spends 2 periods of half hour swimming  = 1 hour.  
actual hiking time  = 3*3 = 9 hours

So total time = 9+1 = 10 hours