An open-air theatre has 25 rows of seats

MATHEMATICS · Multi-part · A Level · Mathematics · Sequences and series · Sequences and series

Problem

An open-air theatre has 25 rows of seats. The first row (nearest the stage) contains 30 seats, and each successive row contains 4 more seats than the previous row. (i) Determine the number of seats in the 25th row. (ii) Find the total number of seats in the theatre.

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