Catherine paid $155.87 for an MP3 player. If the price paid includes a 9% sales tax, which of the following equations can be used to determine the price of the player before tax? How much was the MP3 player before tax?

a) y = 1.09x

$143.00

b) y = 1.09x

$166.90

c) y = 1.9x

$166.90

d) y = 1.9x

$143.00

SmartMathMan Oct 4, 2020

#1**+2 **

Let x be the original price and let y be the price after tax.

Then...

the price after tax = the original price + 9% of the original price

y = x + 9% of x

y = x + 0.09 * x

y = x + 0.09x

y = 1.09x

Then, to find the original price when the price after tax is 155.87, plug in 155.87 for y

155.87 = 1.09x

155.87 / 1.09 = x

143 = x

So the original price is $143.00

hectictar Oct 4, 2020

#2**0 **

THANK YOU SO MUCH!! I'm going to write this out and see if I can remember how to do it. Do you think you could help the guy who posted before me as well?

SmartMathMan
Oct 4, 2020