Solved UPSC CDS/OTA Question
A solved UPSC CDS/OTA PYQ — decoded step-by-step.
Solve it the standard way once — then learn the shortcut.
Q · Number systemMedium · 45s
Find the HCF of 210 and 45.
TopicNumber system
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained — no skipped algebra.
Solve step-by-step using number system concepts. Find the HCF of 210 and 45. → 15
Final Answer: Option C — 15