Solved UPSC CDS/OTA Question
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Q · Ratio and ProportionMedium · 45s
Two numbers are in the ratio 7:9. If each number is increased by 5, the ratio becomes 4:5. Find the numbers.
TopicRatio and Proportion
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.
Let the numbers be 7x and 9x. After adding 5 to each: (7x + 5)/(9x + 5) = 4/5 Cross-multiply: 5(7x + 5) = 4(9x + 5) → 35x + 25 = 36x + 20 Solve: x = 5 Numbers = 7×5 = 35, 9×5 = 45
Final Answer: Option C - 35 and 45