Time and Work Efficiency

CMAT 2025 · Quantitative Techniques & Data Interpretation · Easy · Quantitative Techniques

Amit can do 50% more work than Bhushan in same time. Bhushan alone can do a piece of work in 30 hours. Bhushan starts working and had already worked for 12 hours when Amit joins him. How many hours should Bhushan and Amit work together to complete the remaining work?

  1. A.

    6 hours

  2. B.

    12 hours

  3. C.

    4.8 hours

  4. D.

    7.2 hours

Answer

D

Explanation

Let Bhushan's efficiency be xx units/hr, so Amit's efficiency is 1.5x1.5x units/hr. Total work = 30x30x units. Work completed by Bhushan in 12 hours = 12x12x units. Remaining work = 30x−12x=18x30x - 12x = 18x units. Combined efficiency = x+1.5x=2.5xx + 1.5x = 2.5x units/hr. Time required together = 18x2.5x=7.2\frac{18x}{2.5x} = 7.2 hours.

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