Let, the number of books I can buy = x
Selling price for 1 book = $5.99
So, selling price for x books = $(5.99x)
Given 7.5% is the sales tax.
To find sales tax we have to find 7.5% of $(5.99x)
7.5% of $(5.99x) = (5.99x) × 7.5/100 = (5.99x) × (0.075) = (0.44925x)
So the amount of sales tax = $(0.44925x)
The total cost for buying books including sales tax
= $(5.99x) + $(0.44925x)
=$(6.43925x)
Now given, the shipping cost is 10% of the price.
So to find the shipping cost we have to find 10% of $(6.43925x)
10% of $(6.43925x) = (6.43925x) × (10/100) = (6.43925x) ×(0.1) = (0.643925x)
Shipping charge = $(0.643925x)
So the total cost including shipping charge
= $(6.43925x) + $(0.643925x)
= $(7.083175x)
Now given, there is $50 to spend on books. So to find the number of books we can equate them.
7.083175x = 50
To get x, we have to divide both sides by 7.083175
(7.083175x)/7.083175 = 50/7.083175
x = 7.05898
As we are finding the number of books, so we will take the nearest whole number. Here the nearest whole number is 7.
So the required answer is 7 books.