Question

The corner section of a football stadium has 6 seats on the first row. Each row after that has an additional 3 seats. How many seats would be on the 20th row?
32


63


103


342

Answer 1

9514 1404 393

Answer:

  63

Step-by-step explanation:

The number of seats in a row will give an arithmetic sequence:

  6, 9, 12, 15, ...

The first term is 6; the common difference is 3. The general term is ...

  an = a1 +d(n -1) . . . . . . n-th term of sequence with first term a1, difference d

The 20th term of the sequence is ...

  a20 = 6 +3(20 -1) = 6 +57 = 63

There would be 63 seats on the 20th row.