# Math sequence and series

*label*Algebra

*timer*Asked: May 21st, 2015

**Question description**

A school auditorium has 15 seats in the first row. Each row behind it increases by 4 seats (so the 2nd row has 19 seats, 3rd row had 23 sets etc.) The entire auditorium had 50 rows

Write a recursive AND explicit formula to determine the number of seats in the nth row