Question

The _______ generation in a family tree has 128 members.

Answer 1

The number of members in each generation in a family tree is double the number of members in the previous generation.

So, starting from current generation with 1 member,
Second generation $=1\times 2=2\text{members}$

Third generation $=2\times 2=4\text{members}$

Fourth generation $=4\times 2=8\text{members}$

Fifth generation $=8\times 2=16\text{members}$

Sixth generation $=16\times 2=32\text{members}$

Seventh generation $=32\times 2=64\text{members}$

Eighth generation $=64\times 2=128\text{members}$

Therefore, the eighth generation of a family tree has 128 members.