B3=20
The sum=B1/(1-q)=3*B1 =>q=2/3
B3=B1*q^2
20=B1*4/9 =>B1=45
A geometric progression has a third term of 20 band sum to infinity which is three times the first term. find the first term.
2 answers
=90
2 answers
2 answers
4 answers
1 answer
1 answer