Question

suppose it is 40 degrees inside your refrigerator and 340 degrees inside your oven when the power goes out. The refrigerator temperature starts rising at the rate of 5 degrees per hour. The oven temperature starts dropping at the rate of 45 degrees per hour

Answer 1

I'm assuming that you want to know how many hours until they are the same temperature. Here is the equation you can use to figure it out:

40 + 5h= 340-45h

Here is how I would solve it:

40+ 5h= 340 - 45h
  +45 h          + 45 h

40+50h= 340

-40          -40

50h= 300
 /50   /50

h= 6

It will take 6 hours for the two appliances to reach the same temperature, assuming the power doesn't go out. For reference, they would be at 80 degrees.