An employee works $51$ hours $(51-40$ were overtime hours$)$ during a workweek in December of $2021.$ He earns $$10,000/$month$,$ with his employer paying $1\mathrm{.}5$ times the regular rate of pay for overtime hours. To date, he has earned $$144,100$ during the year. He has requested that his employer withhold $9\%$ of gross pay, which is to be contributed to a $401($k$)$ plan.