Example $12\mathrm{.}2$: Find out the rate of drying and moisture content from the following data :

$\backslash$table$[[$Weight of wet saw dust,Weight of saw dust after drying,Time $($h$)],[250g,230g,0\mathrm{.}5],[250g,215g,0\mathrm{.}75]]$

Dimension of tray $=10cm10cm$

Weight of dry saw dust on tray $=150g$