Help please!? The sales tax on a new car varies directly to(or is directly proportional) the price of the car. If $1,800 in sales tax is paid for a $25,000 car. what is the purchase price of a car worth $1,600 in sales tax? Im totally lost when it comes to variations :(

Question

Help please!? The sales tax on a new car varies directly to(or is directly proportional) the price of the car.  If $1,800 in sales tax is paid for a $25,000 car. what is the purchase price of a car worth $1,600 in sales tax?  Im totally lost when it comes to variations :(

anonymous · Answer

could you show the steps too?

anonymous · Answer

It's a question in proportions.  1800 is to 25000 as 1600 is to x.  Are you with me so far?

anonymous · Answer

yes

anonymous · Answer

but im not supposed to use proportions

anonymous · Answer

its for variations like this is a direct variation

anonymous · Answer

"varies directly" is the same as proportions.  You will use an equation like a/b = c/x.

anonymous · Answer

1800 = a.  25000 = b.  1600 = c.  Just get x

anonymous · Answer

25000/1800 = x/1600 

25000/1800 = 13.89

1800 x 13.89 = 25

1600 x 13.89 = x

anonymous · Answer

the equation they gave to use to use was y=kx ^{n} \]

anonymous · Answer

y=kx squared to n

anonymous · Answer

What is your value for k?

anonymous · Answer

that what i dont know