We have the following:
The first thing is to pass the time from hours to minutes, knowing that 1 hour equals 60 minutes
[tex]6h\cdot\frac{60\min}{1h}=360\min [/tex]Now, we know that you can see 2 sites in 5 minutes, we calculate the number of sites like this
[tex]360\min \cdot\frac{2\text{sites}}{5\min }=144\text{sites}[/tex]Therefore, in 6 hours you will see a total of 144 sites