At $2$:$00$ PM$,$ a thermometer reading $80$ deg F is taken outside, where the air temperature is $20$ deg F$.$ At

$2$:$03$ PM$,$ the temperature reading yielded by the thermometer is $42$ deg F$.$ Later, the thermometer is

brought inside, where the air is at $80$ deg F$.$ At $2$:$10$ PM$,$ the reading is $71$ deg F$.$ When was the

thermometer brought indoors?