Ambu's allowance

27.50 dollars

Well, if d = $4.75 then she will have $(56 - 6*4.75) left

$${\mathtt{56}}{\mathtt{\,-\,}}{\mathtt{6}}{\mathtt{\,\times\,}}{\mathtt{4.75}} = {\frac{{\mathtt{55}}}{{\mathtt{2}}}} = {\mathtt{27.5}}$$

She has $27.5 dollars left.