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प्रश्न
If the common ratio of a G.P. is `2/3` and sum to infinity is 12. Find the first term
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उत्तर
r = `2/3`, sum to infinity = 12 ...[Given]
Sum to infinity = `"a"/(1 - "r")`
∴ 12 = `"a"/(1 - 2/3)`
∴ a = `12 xx 1/3`
∴ a = 4
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