Question

Biswas takes 12 days more than Ashit to complete the particular work. Biswas and Ashit start the work and Ashit leaves the work 12 days before the work is completed. Biswas completes 60% of the overall work. Had Biswas worked independently, the amount of time taken by him to complete the whole work is:
1. 24 days
2. 36 days
3. 12 days
4. 18 days
5.

Answer 1

Correct Answer - Option 2 : 36 days

CALCULATION:

If Ashit takes 'a' days to complete the whole work, then Biswas will take (a + 12) days to complete the whole work.

As Biswas has completed 60% of the work, the remaining 40% work is completed by Ashit. 

∵ Ashit has done 40% of the work before leaving.

∴ Ashit has worked for 2a/5 days.

∵ Biswas has completed 60% of the total work

∴ Biswas has worked for [3(a + 12)]/5 days.

But as Ashit leaves the work 12 days before the Biswas.

⇒ No. of days for which Biswas works = No. of days for which Ashit works + 12 

⇒ [3(a + 12)]/5 = (2a/5) + 12

⇒ 3a + 36 = 2a + 60

⇒ a = 24 days

∴ Time taken by Biswas to complete the work independently = (a + 12) = (24 + 12) = 36 days

• The key to solving this problem is to start from work completed by Biswas.
• The time taken to complete the work ∝ Amount of work.
• Efficiency ∝ 1/Time Taken to complete the work.