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CAT 2019 Slot 2 — QA Question 15

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Anil alone can do a job in 20 days while Sunil alone can do it in 40 days. Anil starts the job, and after 3 days, Sunil joins him. Again, after a few more days, Bimal joins them and they together finish the job. If Bimal has done 10% of the job, then in how many days was the job done?

Answer & solution

  • 13

  • B

    12

  • C

    15

  • D

    14

Solution

Anil in one day can do 1/20th of the work

Sunil in one day can do 1/40th of the work

Anil starts the job and Sunil joins him after three days.

So, Anil would have done 3/20th of the work by the time Sunil joins

After Sunil joins, they both would be doing 3/40th of work everyday

Now, it is known that Bimal joins them after some days and finishes 10% of the work (i.e. 1/10th of the work).

Now, Anil alone had done 3/20th of the work in first 3 days and Bimal completes 1/10th of the work

So, in total they would have done 3/20 + 1/10 = 1/4th of the work.

Remaining work = 3/4th, which would be done by Anil and Sunil together.

Anil and Sunil together comple 1/20th + 1/40th = 3/40th work in 1 day.

Hence, time taken by them to comple 3/4th of the work = 10 days.

Combining everything,

Total number of days = 3 + 10 = 13 days.

Hence, option (a).

CAT 2019 Slot 2 QA Q15: Anil alone can do a job in 20 days while Sunil alone can do it in 40 days. Anil starts the job, and after 3 da — Solution | TheCATExam