Use Law of Cooling:

T0 = initial temperature, TA = ambient or final temperature
First solve for k using given info, T(3) = 42

Substituting k back into cooling equation gives:

At some time "t", it is brought back inside at temperature "x".
We know that temperature goes back up to 71 at 2:10 so the time it is inside is 10-t, where t is time that it had been outside.
The new cooling equation for when its back inside is:

Solve for x:

Sub back into original cooling equation, x = T(t)

Solve for t:

This means the exact time it was brought indoors was about 2.5 seconds before 2:05 PM