Multiply the amount of the notebooks which is 3, by the cost of the notebook, which is $15.85. that is $47.55.
to find how much it costs with the coupon, do the notebook cost and subtract that by 0.75
$47.55 - 0.75 = $46.8
For this type of question, you just need to multiply the percentage with the number
so, the calculation would be
47.2% x 300
47.2/100 x 300
47.2 x 3
= 141.6