A thermometer initially at a steady temperature of $30^{\circ} \mathrm{C}$ is inserted in a water bath maintained at $90^{\circ} \mathrm{C}$. The initial rate of temperature rise of the thermometer is $2{ }^{\circ} \mathrm{C} \mathrm{s}^{-1}$. Assuming first order behavior, after one minute the thermometer reading (in ${ }^{\circ} \mathrm{C}$ ) is $\_\_\_\_$ (rounded off to one decimal place).
