Timmy wants to buy a scooter and the price was $50. when he goes to the store a second time he found that price was marked down 20%. what is the new price?

20% of 50 is the same as writing 50*0.20, so we just do the math on that.
50*0.20=10
Since it was marked down that much, we subtract the found 20% from the 50.
50-10=40
The new price of the scooter is $40.