Ava bought some pens for $ 2 $ 2 each and some pencils for $ 1 $ 1 each. she bought 3 3 more pens than pencils and spent a total of $ 12. $ 12. how many pencils did ava buy?

 Number pencils Ava bought = 2

Explanation:

 Price of pen = 2 $

 Price of pencil = 1 $

 Total money spent = 12 $

 Let the number of pen be a and number of pencil be b.

  2 a + b = 12   Equation 1

 We have, she bought 3 more pens than pencils

   a - b = 3    Equation 2

  Equation 1 +Equation 2,  

           2 a + b +  a - b = 12 + 3

                 3a = 15

                   a = 5

   Substituting in  equation 2

                 5 - b = 3

                b = 2

    Number pencils Ava bought = 2