Answer:
Karoun bought 12n + 15 numbers of pencils.
40 pencils
Explanation:
If there are n numbers of pencils in each box of the pencil then there are 4n numbers of pencils in each package of pencils.
Now, Karoun bought 3 packages of pencils and get (5 × 3) = 15 pencils free of cost.
Therefore, Karoun bought (4n × 3) + 15 = 12n + 15 numbers of pencils. (Answer)
Now, if n = 10 pencils then in each package of pencils there will be 4n i.e. (4 × 10) = 40 pencils. (Answer)