what is the original price was 10% and $37.80

first, I need to turn my 10% in to a fraction:
  10%            ?
--------  =   ______
 100%        37.80

We want to find out what the question mark is ( which the question mark is equal to our answer) 

First, I am going to multiply 10×37.80= 378    
Then, I am going to divide 378 ÷ 100= 3.78 
 
So my ?= 3.78 

I hope this helped :)