From what is there it is nearly impossible to find an exact number so I would say C... hope this helps
1.28 = 128 * 10^-2
128 * (1/10^2)
128 / 10^2
128 / 100
1.28
Because, it's literally the same thing mathematically if you worked it out. Though, as I'm sure you're aware, it's just a much shorter and cleaner way of writing out large or small numbers.
First of all, to find out the amount paid for hours in total,
$48-$18=$30
to find how many hours,
$30÷$5=6hrs