JAMB 2017 · UTME (set 2) · Q2

What is the next number in the series $2, 1, \frac12, \frac14, \dots$ ?

Worked solution (try it first)

Each term is half the one before: $1 \div 2 = \frac12$ and $\frac12 \div 1 = \frac12$ .
So the common ratio is $\frac12$ .
The next term is $\frac14 \times \frac12 = \frac18$ , option D.