Answer:
Part a) The new price is

Part b) The percent decrease is 20%
Part c) The percent decrease is 9.375%
Explanation:
we know that
The original price of a sofa is $500
This price represent the 100%
Part a) If the sofa price decreased by 20%, what is the new price?
Let
x -----> the new price
we know that

so
The new price is equal to the original price multiplied by 0.80

Part b) The company can’t sell the sofa after 3 weeks so they reduce the price to $320. What is the percent decrease?
In this moment the price of sofa is $400
Find the difference between the original price and the new price

using proportion
Find out the percent decrease
Let
x ----> the percent decrease

Part c) If the company reduces the price in week 4 to $290, what is the percent decrease?
In this moment the price of sofa is $320
Find the difference between the original price and the new price
using proportion
Find out the percent decrease
Let
x ----> the percent decrease
