The original cost of a cell phone is x dollars. The phone is on sale for 35% off. Write a simplified expression for the sale cost.

Question

I don't know.

In my math class I've been having a hard time with these. It would be great if you guys would help, thanks.

Answer 1

Dylan, let me give you another problem and see if you can figure it out.  A shirt is x dollars and it's on sale for 20% off.

 

Let's think about how you would figure this out in the store and turn it into an equation.

 

You take the original amount, multiply it by 20%, and subtract it from the original amount.

 

Remember that to turn a percent into a decimal, we move the decimal 2 places to the left,

 

So, we have x - .20x = the new price.

 

Now, remember that the old price is 100%, right?  What percent is the new price if we took 20% off?  80%, right?

 

So, we can either subtract x - .20x to get .80x, or we can take the 20% from the 100% to get the 80%, or .80x.

 

I hope this helps.

Answer 2

original cost - (percentage off)(original cost) = sale cost

 

 

x - 0.35x = 0.65x = sale cost

 

I hope that helps.