Baking muffins: Chocolate muffins are baking in a 350-degree oven. Let M = M(t) be the temperature of the muffins t minutes after they are placed in the oven, and let D = D(t) be the difference...

Baking muffins: Chocolate muffins are baking in a 350-degree oven. Let M = M(t) be the temperature of the muffins t minutes after they are placed in the oven, and let D = D(t) be the difference between the temperature of the oven and the temperature of the muffins. Then D satisfies Newton’s law of cooling, and its equation of change is

a. If the initial temperature of the muffins is room temperature, 73 degrees, find a formula for D.

b. Find a formula for M.

c. The muffins will be done when they reach a temperature of 225 degrees. When should we take the muffins out of the oven?