Correct Answer - Option 3 : 13
Calculation:
Anil, Sunil and Bimal together finished the job
Bimal has done 10% of the job
⇒ Job done by Anil and Sunil = (100% – 90%) of the job
⇒ 90% of the job
Total job is the LCM of 20, 40
⇒ 40
Efficiency of Anil = 40/20
⇒ 2
The efficiency of Sunil = 20/20
⇒ 1
Let the number of days Anil and Sunil done the job together be D days
Anil has done the job alone for three days and then Sunil joined him and they have together done the job
⇒ 2 × 3 + D(2 + 1) = 90/100 × 40
⇒ 3D = 36 – 6
⇒ D = 30/3
⇒ D = 10
Total time to complete the job = D + 3
⇒ 13 days
∴ In 13 days the job was done.