Which number should replace the question mark (?) in the series below?
7, 21, 63, ?, 567
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 189
Each term is three times the term before:
\(7\times3=21\)
\(21\times3=63\)
\(63\times3=189\)
Check: \(189\times3=567\), the last term
So the missing number is 189.