Question

X can do a piece of work in 24 days when he had worked for 4 days y joined him if complete work was finished in 16 days y can alone finish that work in

Answer 1

X can complete the work in 24 days.
so,work done by X in 1 day=1/24
Therefore,
Work done by him in 4 days =
$\frac{1}{24} \times 4 = \frac{1}{6}$
They finish it in (16-4)=12 days.
So, work done by both in one day=
$\frac{ \frac{6}{5} }{12} = \frac{5}{72}$
Now,work done in 1 day by X alone =1/24
Hence,work done by Y alone in 1 day=
$\frac{5}{72} - \frac{1}{24} = \frac{1}{36}$
So,Y can alone finish the work in 36 days..