I'm assuming that you want to divide the fraction 23/0.3 by the fraction 20/24.
First of all, the fraction 20/24 can be simplified, since both numerator and denominator are multiple of 4:
Secondly, dividing by a fraction is the same as multiplying by the inverse of the fraction, i.e. if you have to divide by a/b, it's the same as multiplying by b/a.