A multi-storied office building has a total of 17 rows of parking spaces. There are 20 parking spaces in the first row and 21 parking spaces in the second row. In each subsequent row, there are 2 more parking spaces than in the previous row. The total number of parking spaces in the office building is
Explanation:
Observe that the last 16 rows form an A.P. with a = 21, d = 2 and n = 16. The term before that is 20.
Hence, sum = (19 + 1) + A.P. of 16 terms
Hence, this can even be considered as an A.P. of 17 terms with a = 19 and d = 2
∴ Total parking spaces = 1 + (17/2) × [2(19) + 16(2)] = 1 + 17(19 + 16) = 596
Hence, option (c).
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