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MathsMediumMCQ2014 ยท 11 Apr Online

Q64.In a geometric progression, if the ratio of the sum of first 5 terms to the sum of their reciprocals is 49 , and the sum of the first and the third term is 35. Then the first term of this geometric progression is: (1) 7 (2) 21 (3) 28 (4) 42

What This Question Tests

This question tests the derivation of the ratio of the sum of terms to the sum of reciprocals in a GP and solving for the first term using additional given conditions.

Concepts Tested

Sum of terms in GPGP of reciprocalsSolving system of equations

Formulas Used

Sn = a(rโฟ-1)/(r-1)

Sum of reciprocals in GP S'n = (1/a) * (1-(1/r)โฟ) / (1/r-1)

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