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
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
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?