Question

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?

• A. 14
• B. 13
• C. 15
• D. 12

Answer 1

The Correct Option is B

Let the total work be 40 units.
The amount of work done by Anil in one day is \(\frac{40}{20}=2\) units.
Similarly, the amount of work done by Sunil in one day is \(\frac{20}{20}​=1\) unit.
Bimal contributes 10% of the work, which is 4 units. The remaining work is \(40−4=36\) units and is done by Anil and Sunil.

Let's denote the number of days Anil took as \(x\). Therefore, Sunil took \(x−3\) days.
The equation representing the work done is \(2x+(x−3)=36.\)
Solving for x:
\(2x+x−3=36\)
\(3x=39\)
\(x=13\)

Therefore, Anil took 13 days to complete the work.