Solved IB ACIO Question
A solved IB ACIO PYQ — decoded step-by-step.
Solve it the standard way once — then learn the shortcut.
Q · Missing Numbermedium · 45s
What is the missing number in the series? 3, 6, 9, 12, ?
TopicMissing Number
Question Typemultiple choice
Difficultymedium
Marking+1 / −0.25
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained — no skipped algebra.
The series increases by 3; after 12 comes 15.
Final Answer: Option B — 15