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 · Mixture and AlligationMedium · 45s
Two vessels contain spirit and water mixed respectively in the ratio of 1 : 4 and 4 : 1. Find the ratio in which these are to be mixed to get a new mixture in which the ratio of spirit to water is 1 : 3 .
TopicMixture and Alligation
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.
Vessel 1 Vessel 2
1/5 4/5
\ /
Desired = 1/4
/ \
(4/5 − 1/4) (1/4 − 1/5)
Calculate differences:
Left difference = 4/5 − 1/4 = (16 − 5)/20 = 11/20
Right difference = 1/4 − 1/5 = (5 − 4)/20 = 1/20
Ratio of mixing = Right : Left = 11 : 1
Final Answer: Option A - 11 : 1