A customer buys a book that has an original selling price of $38. The book is discounted 25%. The customer must pay a 4% sales tax on the discounted price of the book.
we have that
100%-25%=75%=75/100=0.75
so
the payment before the sales tax is equal to
$38*(0.75)=$28.50
100%+5%=105%=105/100=1.05
the payment after the sales tax is equal to
$28.50*(1.05)=$29,93
answer is $29.93