Problem: In a geometric progression whose terms are positive, any term is equal to the sum of the next two following terms. Then the common ratio is
Answer Choices:
A. 1
B. about 25
C. 25−1
D. 21−5
E. 52
Solution:
arn=arn+1+arn+2;∴r2+r=1;∴r=(5−1)/2.