3log2+log20÷log1•6

3log2+log20÷log1•6

= log (2^3) + log 20 ÷ (log1 + log6)
= log (8*20) ÷ log6
= log 160 / log 6

I think we had

3log2 + log20 - log1.6 = log160/1.6 = log100 = 2