We can represent the cost of the notebooks with by saying 0.75n, and the cost of the pens by saying 0.55p.
0.75n+0.55p will be the total cost before tax. Now, we need to add on tax. Tax will be 0.0625 times the total amount, so we can represent the cost by saying
(0.75n+0.55p) + 0.0625(0.75n+0.55p), so the answer is B.
