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Find the sum: 1 + 3 + 5 + 7 + … + 99 (first 50 odd numbers):

A100
B250
C500
D2500
Answer & Solution
Correct answer: D. 2500
The sum of the first n odd natural numbers is n². For n = 50: 50² = 2500. (Quick alternative: S = n/2 × (first + last) = 50/2 × (1 + 99) = 25 × 100 = 2500.)
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