An arrangement of biliard balls has 5 balls in the first row and 16 rows in all in each successive row one ball is added.
What is the explicit rule for this situation, and how many balls will be
in thelothrow?
Drag and drop the answers into the boxes to match the situation

I got the explicit rule would be an = 4+n, and the number of balls on the 16th row is 20!

(this is correct but i couldnt comment on the old question to put my answer haha)