When Marcus wakes up, his house is 40 degrees. He spends 3 hours baking, and every hour the oven is on it raises the house's temperature by 5 degrees. Then Marcus opens a window for 30 minutes, and the house cools down 2 degrees for every 10 minutes the window is open. What is the house's final temperature?
First find the total temperature increase from the oven: 3 hours * 5 degrees/hour = 
<gadget id="calculator">3*5</gadget>
<output>15</output>
15 degrees.
Then add that amount to the starting temperature: 15 degrees + 40 degrees = 
<gadget id="calculator">15+40</gadget>
<output>55</output>
55 degrees.
Then divide the time the window is open by 10 minutes to find how many 2-degree temperature decreases there are: 30 minutes / 10 minutes = 
<gadget id="calculator">30/10</gadget>
<output>3</output>
3.
Then multiply the number of decreases by the amount of each decrease: 3 * 2 degrees = 
<gadget id="calculator">3*2</gadget>
<output>6</output>
6 degrees.
Then subtract that amount from the house's temperature after baking to find the final temperature: 55 degrees - 6 degrees = 
<gadget id="calculator">55-6</gadget>
<output>49</output>
49 degrees.

<result>49</result>