Answer
Stone house: 9 hours
Wood house: 3 hours
Work Step by Step
We divide the value of Q by the rate at which heat is absorbed to find:
$ \Delta t = \frac{ \Delta Q}{10^5} = \frac{75 \times 2000 \times .2 \times 30}{10^5 } = 9 \ hours$
For the wood house:
$\Delta t = \frac{ \Delta Q}{10^5} = \frac{15 \times 2000 \times .33 \times 30}{10^5 } = 3 \ hours$
