# Formulating an expression

• Apr 11th 2011, 10:16 PM
jay1
Formulating an expression
I need help understanding how to write an expression and explain how I arrive at the answer for the following:

You are trying to decide how to most efficiently use your oven. You do not want the oven running at a high temperature when you are not baking, but you also do not want to waste a lot of time waiting for the oven to reach the desired baking temperature.

The instruction manual on the industrial oven suggests the oven temperature will increase by 35 degrees Fahrenheit per minute. When the oven is initially turned on, the temperature is 60 degrees Fahrenheit. What will the temperature of the oven be after 9 minutes?
• Apr 11th 2011, 10:21 PM
mr fantastic
Quote:

Originally Posted by jay1
I need help understanding how to write an expression and explain how I arrive at the answer for the following:

You are trying to decide how to most efficiently use your oven. You do not want the oven running at a high temperature when you are not baking, but you also do not want to waste a lot of time waiting for the oven to reach the desired baking temperature.

The instruction manual on the industrial oven suggests the oven temperature will increase by 35 degrees Fahrenheit per minute. When the oven is initially turned on, the temperature is 60 degrees Fahrenheit. What will the temperature of the oven be after 9 minutes?

T = 35t + 60.
• Apr 12th 2011, 09:21 AM
HallsofIvy
Another way of looking at it: "The instruction manual on the industrial oven suggests the oven temperature will increase by 35 degrees Fahrenheit per minute"
After the first minute, the temperature will be 60+ 35= 95 degrees. After the second minute, 95+ 35= 130 degrees. After the third minute, 130+ 35= 165 minutes. Do that 6 more times. Of course, mr fantastic's method- multiplying instead of adding the same thing repeatedly- is faster.