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 · Average Medium · 45s
TopicAverage
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.
Sum of 8 numbers = 20 X 8 = 160
Sum of first two numbers = 2 X 15.5 = 31
Sum of next three numbers = 3 X (64/3)
= 64
Let the 6th, 7th, 8th no. is x, x+4 and x+7 respectively
x + x + 4 +x + 7 = 160 - 31 - 64 = 65
3x + 11 = 65
x = 18
So, 8th no. = 25
Final Answer: Option B - 22