Question $9$

$1$ pts

In $2010,$ $$1\mathrm{.}00$ U$.$S$.$ bought $8\mathrm{.}24$ Chinese yuan and in $2012$ it bought $6\mathrm{.}64$ Chinese yuan. How many U$.$S$.$ dollars could $1$ Chinese yuan purchase in $2010$ and $2012?$

$2010$: $.12$ U$.$S$.$ dollars; $2012$: $.15$ U$.$S$.$ dollars

$2010-12$ US dollars: $2012$: $1\mathrm{.}5$ U$.$S dollars

$2010$: $82$ U$.$S$.$ dollars; $2012$: $66$ U$.$S$.$ dollars

$2010\mathrm{.}15$ U$.$S dollars; $2012$: $11$ U$.$S$.$ dollars