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?

Question

PYQPulse · Accepted Answer

1260

PYQPulse · Answer

Explanation: First row = 100 - 20x4 = 20; total = 21 x (20 + 100)/2 = 1260.

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?

Answer: A. 1260

Explanation

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?

Answer: A. 1260

Explanation