Topic : GP

Q2. The sum of the first 3 terms of a GP is 1 and the sume of the next three terms is 27. Determine the first term, the common ratio and the sum of the GP.

Asked by Pankaj | 7th Oct, 2018, 07:05: PM

Expert Answer:

let a,ar,ar2,ar3,.....be the terms
a+ar+ar2=1
a(1+r+r2)=1......(1)
2nd condition
ar3(1+r+r2)=27......(2)
 
r3=27.....from(1)
r=3
put in (1)

Answered by Arun | 8th Oct, 2018, 12:26: PM