JAMB 2013 · UTME · Q2

Convert $27_{10}$ to a number in base three.

Worked solution (try it first)

$27 = 3 \times 3 \times 3 = 3^3$ .
So 27 is one lot of $3^3$ and nothing else: $1 \times 27 + 0 \times 9 + 0 \times 3 + 0$ .
So $27_{10} = 1000_3$ , option B.