In $1973$ the horse Secretariat ran $1\mathrm{.}5$ miles in $2$ minutes and $24$ seconds, in the Belomt Stakes. $$

$($A$)$ calculate his average speed, in SI units. $$

$($B$)$ Calculate the ratio of the average speeds of Secretatiat and a human sprinter who runs the $100$ m dash in $9\mathrm{.}8$ seconds.