MAth

posted by .

The front row of a stadium has 25 seats. Each of the other rows has two more seats than the row in front of it. how many seats are there altogether in the first 20 rows?

i know how to do this in the "long" way but how do you do this is a "shorter" way by finding the pattern? Explain please!!

  • MAth -

    The seat count forms an arithmetic sequence

    25,27,29...

    where a = 25, d=2

    The sum of the 1st 20 terms is thus
    S20 = 20/2 (2*25 + 19*2) = 880

  • MAth -

    what equation is that?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    Determine the seating capacity of an auditorium with 10 rows of seats if there are 10 seats in the first row, 16 seats in the second row, 22 seats in the third row, 28 seats in the forth row, and so on ?
  2. Math

    an auditorium has 50 rows of seats. THe first row has 20 seats, the row has 21 seats, the third row has 22 seats, and so on. each row having one more seat than the previous row. How many seats are there all together?
  3. math

    In a movie theater, Theater A has 30 seats in the first row. Each next row has 4 more seats in it than the previous row has. 1) How many seats are in the 4th row?
  4. math (plz help)

    In a movie theater, theater A has 30 seats in the first row. Each next row has 4 more seats in it than the previous row has. 1) How many seats are in the 4th row?
  5. arithmetic

    PLEASE I REALLY NEED HELP WITH THIS The seats at a local baseball stadium are arranged so that each row has five more seats than the row in front of it. If there are four seats in the first row, how many total seats are in the first …
  6. Math

    An auditorium has 30 rows of seats. It has 20 seats on the first row, 24 seats on the second row, 28 seats on the third row, and so on. 1. How many seats are there in the 20th row?
  7. maths

    There are 21 rows of seats in an amphitheatre. Each row has 4 seats more than the row in front. The last row has 100 seats. How many seats are there altogether in the amphitheatre
  8. Math

    A section in a stadium has 20 seats in the first row, 23 seats in the second row, increasing by 3 seats each row for a total of 38 rows. How many seats are in this section of the stadium?
  9. Math

    a stadium has 75 rows starting with 200 seats in the first row. Each successive row has two additional seats. How many seats are in the 50th row?
  10. Math

    An auditorium has 150 rows of seats. The first row has 15 seats, the second row has 17 seats, the third row has 19 seats, and so on, each row having two more seats than the previous row. How many seats are there together in the auditorium.

More Similar Questions