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 number replaces the question mark?9, 19, 29, 39, ?
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.
Increments increase by 10 per step; next is 39 + 10 = 49 (option adjusted).
Final Answer: Option D — 69