Question 4 • Mathematics III
The first term of the series 1 + 3 + 9 + 27 + 81 is 1, so A₁ = 1. Divide each term by the term before it to find the common ratio: 3 ÷ 1 = 3, and the same ratio holds for the remaining terms. Therefore, the correct choice is B: A₁ is 1 and r is 3.
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