Multiple choice

Amit can do 3 4th of work in 5 6 days in comparison to Bhanu. If both complete the work in 10 days doing together then in how many days Bhanu alone can finish the work?

  1. 18

  2. 21

  3. 19

  4. 21.5

  5. 22

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If Amit does 3/4 of work in 5/6 of Bhanu's time, Amit's rate : Bhanu's rate = (3/4)/(5/6) = 9:10. Together in 10 days: (9+10)/10k = 1/10, so k = 1. Bhanu alone: 10/1 = 10 days for full work. But wait - let me recalculate. Amit's efficiency = (3/4 work)/(5/6 time) = 9/10 of Bhanu. So if Bhanu takes x days, Amit takes x/(9/10) = 10x/9 days. Together: 1/x + 9/(10x) = 1/10. 19/(10x) = 1/10, x = 19. Bhanu takes 19 days.