Consider the set of numbers {1, 3, 32, 33,…...,3100}. The ratio of the last number and the sum of the remaining numbers is closest to:
Explanation:
The last number is 3100.
Sum of the remaining numbers = S = 1 + 3 + 32 + … + 399 …(1)
This is a GP with a = 1; r = 3 and n = 100
∴ S = 1×(3100-1)3-1 ∴ Required ratio = 31001×(3100-1)2 = 21-13100 ∵ 1/3100 is approximately zero, hence it can be ignored. ∴ Ratio = 2 Hence, option (b).
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