The 8th term of a G.P. is 1/81. Determine the first term if the common ratio is 1/3.

Answer 1

term(8) = a r^7
1/81 = a(1/3)^7
1/3^4 = a(1/3^7)
a = 3^3 = 27

sequence is : 27, 9, 3, 1, 1/3 , 1/9, 1/27, 1/81, ....