I suppose that when you write "log^6" , you want to say log₆
Change of base formula:
loga b=logc b / logc a
log₆ 120=ln 120 / ln 6=2.67
Answer: log₆ 120=2.67
First you need to turn this into an improper fraction. Then, using your improper fraction, you simplify
She will solve 20 problems in 2.5 hours, 4*5 thirty minute sessions=20.

The two other prime factors are
3 and 11