Answer:
13 trails
Step-by-step explanation:
The histogram shows following numbers of trails:
- 0 - 6 km long - 5 trails;
- 6 - 12 km long - 9 trails;
- 12 - 18 km long - 7 trails;
- 18 - 24 km long - 3 trails;
- 24 - 30 km long - 4 trails;
- 30 - 36 km long - 1 trail;
- 36 - 42 km long - 3 trails.
So, there are 5 trails with length less than 6 km and 4 + 1 + 3 = 8 trails that are at least 24 km long.
In total, 5 + 8 = 13 trails
