Answer:
18 tours are offered
Explanation:
So 1/3 of a hour is 20 mins, so every 20 mins a tour is offered so we know 1 hour equals to 3 tours offered so
10:00 to 11:00 is 3, 11:00 to 12:00 is 3, 12:00 to 1:00 is 3, 1:00 to 2:00 is 3, 2:00 to 3:00 is 3, 3:00 to 4:00 is 3.
6 hours times 3 equals, 18 tours are offered