A mixture of benzene and toluene containing $10\%$ by mole benzene is continuously distilled at a rate of $1000$ kmol$/$h in a distillation column. $95\%$ of the benzene in the feed is recovered as distillate product which contains $98\%$ benzene and $2\%$ toluene Calculate the following

$($a$)$ The moles of bottom product

$($b$)$ The composition of the bottom product