Question

$A,B$ and $C$ together can complete a piece of work in $10$ days. All the three started working at it together and after $4$ days $A$ left. Then $B$ and $C$ together completed the work in $10$ more days. $A$ alone could complete the work in :

• A. $15$ days
• B. $16$ days
• C. $25$ days
• D. $50$ days

Answer 1

The correct option is C $25$ days

Work done by $A,B,C$ in $1$ day is $\frac{1}{10}$

After $4$ days the work left is $\frac{6}{10}$

Work done by $B,C$ in $1$ day is $\frac{6}{100}$

So, Work done by $A$ in one day is $\frac{1}{10}-\frac{6}{100}=\frac{1}{25}$

so $A$ takes $25$ days to complete the work.