The value of maggie's car decreased by 10% since last year, when she bought it. if the car is now worth $11,000.00, how much was the car worth when she bought it?

The value is decreased by 10%. This means that current price is 100%-10%=90% of the original price. Now we can solve this by using ratios

90%             $11000
100%           $x

Now we cross multiply numbers and solve it for x:
90*x = 100 * 11000
90x = 1 100 000
x= 1 100 000 / 90
x= $12 222,22

When Maggie bought a car theprice was $12 222,22

Cdoes not have two variables