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GATE 2017 ME (ME2) – Question 7

General Aptitude · Quantitative Aptitude: Arithmetic and Number Computation · 2 marks · Multiple choice

X bullocks and Y tractors plough a field in 8 days. Halving bullocks and doubling tractors reduces the time to 5 days. X bullocks alone would take ______ days.

  1. 30
  2. 35
  3. 40
  4. 45

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Show answer and explanation

Correct answer: (A) 30

Explanation

Let b and t be the daily field fractions completed by X bullocks and Y tractors. Then b+t=1/8 and b/2+2t=1/5. Substituting t=1/8−b gives b/2+1/4−2b=1/5, hence b=1/30. The bullocks alone require **30days, A**.