Hello!
First, let's consider the value of $48.88 as 100%. Then, we have to find how many correspond to 8% of it. We can calculate it using the rule of three:
[tex]\begin{gathered} \frac{48.88}{x}=\frac{100}{8} \\ \\ \text{ multiplying across} \\ x\cdot100=8\cdot48.88 \\ 100x=391.04 \\ x=\frac{391.04}{100} \\ x\cong3.91 \end{gathered}[/tex]So, the sales tax is $3.91.
Now, we have to add the price of the coat with the sale tax:
$48.88 + $3.91 = $52.79
If she pays all together, the cost will be $52.79.