Having some trouble with logs. I have attached two questions. The first question I completed and wanted a second opinion on my answer. The second question confuses me (I think it's 5)

A)my answer is 18.287711238. I got log (subscript 2) 320000, then used the equation to change the base of the log to 10 so I could use a calculater. Is this correct?

B)my answer is 5 (guess)