Question

Need help asap please explain

The sum of the first six terms of the geometric sequence 1, 2, 4, 8, ... is equal to the sum of
the first six terms of an arithmetic sequence that also has 1 as its first term. What is the
fifth term of the arithmetic sequence?

Answer 1

Isn’t it 16. I’m sorry but that’s what the pattern of the geometric sequence looks as if to be correct.

Answer 2

Explanation:

sum of first six terms of given G.P.=1+2+4+8+16+32=63

let d be c.d. of A.P.

first six terms are 1,1+d,1+2d,1+3d,1+4d,1+5d

1+1+d+1+2d+1+3d+1+4d+1+5d=63

6+15d=63

15d=63-6=57

divide by 3

5d=19

d=19/5=3.8

fifth term=1+4d=1+3.8*4=1+15.2=16.2