19. At a certain time, a thermometer reading \( 70^{\circ} \mathrm{F} \) is taken outdoors where the temperature is \( 15^{\circ} \mathrm{F} \). Five minutes later, the thermometer reading is \( 45{ }^{\circ} \mathrm{F} \). After another five minutes, the thermometer is taken back indoors where the temperature is fixed at \( 70^{\circ} \mathrm{F} \). What is the thermometer reading ten minutes after it was brought back indoors? After the thermometer is brought back indoors, when will the reading be \( 69{ }^{\circ} \mathrm{F} \) ?
a. \( \quad 42.93^{\circ} \mathrm{F}, 45.22 \mathrm{~min} \)
b. \( \quad 58.50^{\circ} \mathrm{F}, 30.14 \mathrm{~min} \)
c. \( \quad 64.37^{\circ} \mathrm{F}, 26.89 \mathrm{~min} \)
d. \( \quad 60.43^{\circ} \mathrm{F}, 36.72 \mathrm{~min} \)
