The first term of a geometric progression is 350. If the sum to infinity is 250, find the common ratio.
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
Correct Answer: Option B
Explanation:
\(S_{\infty} = \frac{a}{1 - r}\) (Sum to infinity of a GP)
\(250 = \frac{350}{1 - r} \implies 250(1 - r) = 350\)
\(350 = 250 - 250r \implies 350 - 250 = -250r\)
\(250r = -100 \implies r = \frac{-100}{250} = -\frac{2}{5}\)
\(S_{\infty} = \frac{a}{1 - r}\) (Sum to infinity of a GP)
\(250 = \frac{350}{1 - r} \implies 250(1 - r) = 350\)
\(350 = 250 - 250r \implies 350 - 250 = -250r\)
\(250r = -100 \implies r = \frac{-100}{250} = -\frac{2}{5}\)