Question 448085
I'll do the first one to get you started. 



Let x = original price of the car (ie the price before the discount is applied. So this means that the original price is more than the sale price). 



Since the sale price is 20% off of the original price, this means that we have the following


Sale price = Original Price - 20% of original price


In other words, we're subtracting 20% of the original price from the original price.



In our problem, we let x be the original price. Now 20% of the original price x is 0.2x (note: 20% in decimal form is 0.2, just move the decimal point 2 spots to the left)



So we now get


Sale Price = x - 0.2x



But we also know that the sale price was $12,590. So this means that



12590 = x - 0.2x



Now combine like terms on the right side to get



12590 = 0.8x



Note: x - 0.2x = 1x-0.2x = (1-0.2)x = 0.8x



Now we want to isolate x. We do this by noticing that 0.8x means "0.8 <u>times</u> x". So to undo multiplication, we use division. This means we divide both sides by 0.8



Divide both sides by 0.8 to isolate x and get



12590/0.8 = x



15737.5 = x <----- Use a calculator to get this



x = 15737.5



So because x = 15737.5 and x is the original price, this means that the original price was $15,737.50



Notice how the original price ($15,737.50) is more than the sale price ($12,590). Also, notice that if you take 20% off of the original price ($15,737.50), you get the sale price ($12,590). Let's check that


Check:


20% of $15,737.50 is 0.2*15737.50 = 3147.5



Subtract this from the original price to get



15737.50 - 3147.5 = 12590



So this verifies the answer.