The thermometer nicely obeys a unit normal distribution so we just want the area under the Gaussian from [tex]z = -.75[/tex] to [tex]z=-.07[/tex]. That's a sketch of the standard bell curve with the region between -.75 and -.07 shaded in; I'll leave the actual sketching to you.
The standard normal table often only lists [tex]\Phi(z)[/tex], the integral of the unit normal from negative infinity to z, for z>0. For negative z we need [tex]1 - \Phi(-z)[/tex],
[tex]p = \Phi(-.07) - \Phi(-.75) = (1- \Phi(.07)) - (1-\Phi(.75)) = \Phi(.75) - \Phi(.07)[/tex]
[tex]\Phi(.07)=0.52790[/tex]
[tex]\Phi(.75)=0.77337[/tex]
[tex]p = 0.77337-0.52790=0.24547 [/tex]
We can round that to [tex]p=\frac 1 4[/tex]
