Basic Arithmetic Help, Price calculation.

Question

You can buy 5 more extra books with $ 75, due to a reduction of price by 20%. What is the original and current price of one book?

Answer 1

Original price is x

Reduced price is 0.80 x

Originally you can buy 75/x books

Now you can buy 75/0.8x

75/0.8x = 75/x + 5

Multiply by 0.8x

75 = 60 + 4x

15 = 4x

x = 15/4 = $ 3.75 (so originally you can buy 75 / 3.75 = 20 books)

Current price = 0.8x = $ 3.00 (now you can buy 75/3 = 25 books)

Answer 2

Hello Krugen,

With the reduced price, we know that $75 buys us 5 books, meaning that the price for one book is $15 (75/5=15). This amount, $15, is the 20% off, reduced price. To find the original price of one book, we must set up an equation. If "x" is the original price of the book, then our equation will be:

x - 0.2x = 15

(If you think about how we calculate 20% off of something, we first multiply the original price by the decimal form of the percent value and then subtract this amount from the original price. For example, to find 15% off of $25, we first multiply 0.15*25, giving us 3.75. Then we know we are getting $3.75 off of the original $25 price and will therefore pay $21.25.)

Once we have our equation, we can solve for "x":

x - 0.2x = 15

0.8x = 15

x = $18.75

Therefore, the original price of one book was $18.75.

I hope this helps!