Mathematics

Mathematics

Problem

Suppose a1,a2,…,an,…a_1, a_2, \dots, a_n, \dots be an arithmetic progression of natural numbers. If the ratio of the sum of first five terms to the sum of first nine terms of the progression is 5:175:17 and 110<a15<120110 < a_{15} < 120, then the sum of the first ten terms of the progression is equal to (a) 290 (b) 380 (c) 460 (d) 510

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