Multiple choice

The efficiency of A, B and C are in the ratio 5 : 6 : 9. Working together, they can complete a work in 18 days. In how many days can B alone complete 25% of that work?

  1. 18

  2. 10

  3. 15

  4. 16
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total efficiency = 5+6+9 = 20. Total work = 20 * 18 = 360 units. 25% of work = 90 units. B's efficiency = 6. Time for B = 90 / 6 = 15 days.

AI explanation

Let their efficiencies be 5x, 6x, and 9x units per day, making their combined daily efficiency 20x units. Working together for 18 days, the total work equals 18 multiplied by 20x, which is 360x units. Since B alone has an efficiency of 6x units per day, B would need 360x divided by 6x, or 60 days to complete the entire work. To complete 25 percent of that work, B requires 25 percent of 60 days, which equals 15 days.

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