Question

the fourth term of a GP is 2/3 and 7th term is 16/81 the GP

Answer 1

ar^3=2/3 (1)and ar6=16/81(2)
divide both them
r^3=8/27
put r^3 in eq first (1)
then get a (8/27)=2/3
finally get a=9/4
The first term of the geometric series is 9/4