A college lecture hall has 15 rows of seats. The first row has 18 seats the next row has 20 seats, and the third row has 22 seats. How many seats are in the last row?

Write the rule for the number of seats in the nth row.

You can ride your bike around your block 6 times and the whole neighborhood 5 times in 16 minutes. you can ride your bike around your block 3 times and the whole neighborhood 10 times in 23 minutes. how long does it take you to ride around the neighborhood?