Question 1 • Precalculus
A geometric series converges when the absolute value of its common ratio is less than 1. In choice D, each term is one-fourth of the previous term: (1/20) ÷ (1/5) = 1/4, and the later terms follow the same ratio. Since |1/4| < 1, choice D, the series 1/5 + 1/20 + 1/80 + 1/320 + ···, converges.
AI-written and checked against the verified answer.