A wet solid containing $70\%$ water is mixed with recycle dry solid to reduce the water content to $50\%$ before being admitted into the granulator. The solid leaving the granulator is fed to a dryer where it is brought into contact with dry air initially containing $0\mathrm{.}25\%$ water by weight. In the dryer, the air picks up moisture and leaves with a moisture content of $5\%.$ The solid leaving the dryer contain $20\%$ water. A portion of solid is recycled.

For $1000k\frac{g}{h}$ of wet solid sent to the granulator as fresh feed, determine:

a$)$ The amount of solid recycled

b$)$ The circulation rate of air in the drier on the dry basis

$8$