0 RISHABH ANANTIntermediate Asked: December 4, 20202020-12-04T22:02:56+05:30 2020-12-04T22:02:56+05:30In: BM/LRS (CA Foundation) GEOMETRIC PROGRESSION 0 Question no 34 Please explain it Share Sorry, you do not have permission to answer to this question. 1 Answer Oldest Gitika Chandirani11 Pro 2020-12-05T16:40:01+05:30Added an answer on December 5, 2020 at 4:40 pm Let 1st term = a Common ratio = r a+ar= 15 a=15/1+r…..i) t2= a/1+r – 15 ar= a/1-r – 15….ii) Put i in ii r(1-r)= 1-1+r² 2r²-r= 0 2r-1= 0 r= 1/2 Hence a= 10 Sum a/1-r = 20
Let 1st term = a
Common ratio = r
a+ar= 15
a=15/1+r…..i)
t2= a/1+r – 15
ar= a/1-r – 15….ii)
Put i in ii
r(1-r)= 1-1+r²
2r²-r= 0
2r-1= 0
r= 1/2
Hence a= 10
Sum a/1-r
= 20