If the median A and mode B of following distribution satisfy the relation 7 (B - A) = 9C, then find the value of C : Class 0-30: freq 4; 30-60: freq 5; 60-90: freq 7; 90-120: freq 4.
Answer key: official UPPSC key
Partial paper: 145 of 150 questions · renumbered after deletions · 5 questions deleted from the official key are absent