Question

last month you spent $20 on clothing. This month you spent 180% of what you spent last month. Set up a proportion to model this situation.

Answer 1

First the absolute would decrease

20 - 15 = $5  

Then the percent decrease is the absolute decrease divided by the the original price (part/whole).  

percent decease = 5 / 20 = 0.25  

Multiply and divide 0.25 to obtain percent.  

percent decease = 0.25 = 0.25 * 100 / 100 = 25 / 100 = 25%

Answer 2

Ik I am late to this question, but I am going to answer it for those who are struggling.

The model for this situation is X/20 = 180/100