In early 2012, the price of gas was $3.64. This represents a 40% increase from early 2009. What was the price of gas in early 2009?

Question

anonymous · Answer

3.64/1.4 = (what you are looking for)

How?

in 2009 years it represents 100% of whole price, therefore in 2012 it will be 100% + 40% = 140%

anonymous · Answer

thank you that helped a lot

anonymous · Answer

... and you make equation :
3.64/1.40 = x/1

anonymous · Answer

welcome

anonymous · Answer

Brian and Ron went to TGI Friday’s for dinner. After adding a 20% tip, they paid a total of $42. What was the cost of the meal before they added the tip?

anonymous · Answer

yet again, same situation.
let's say theyr price of meal is equal 100 %, and you add 20 % extra

so :

100% +20% is what you are given.

therefore  (i'll add example so you get how it's done step by step)

x1 - y1
x2 - y2

x1*y2 = x2*y1
and you use that to make:

42 - 120 %
x - 100%

helps?