Question Detail
Question
The sum to infinity of a GP is 12. Its first term is 8. Find the common ratio.
Correct Answer
Option A is the correct answer.
Detailed Explanation
S_∞ = a/(1−r) → 12 = 8/(1−r) → 1−r = 8/12 = 2/3 → r = 1−2/3 = 1/3.
Hint
Use S_∞ = a/(1−r) for |r|<1.