please help me with this

This means 2^(10x) = 9.10x = log9, so x = log9/10, which is B.

You are very welcome1

:P

The right answer is A

x = ln(9) / 10*ln(2)         or          x = [ log(9) / log(2) ] /10 = 0.316992414278

300 * 2^{3.16992414278} = 2700