Math Journal #1:

Question #3 Page. 479:

3. Over the last 10 years, data was recorded for the number of cups of hot chocolate sold at BGB Senior High School. It was found from the data that the warmer the weather, the less cups of hot chocolate were sold. The data can be modelled by the formula N(T) = 150 – 10T, where N(T) is the daily number of cups of hot chocolate sold when the average daily temperature is T degrees Celsius.

A) Determine the value of N(-5)

B) Write in words the meaning of N(-5)

C) what was the average temperature if 190 cups of hot chocolate were sold

D) Explain how to estimate the lower limit of the domain of the relation

This question seemed a little bit confusing to me when I first read it. There is lots of data and information being thrown at you, and this was a bit overwhelming at first, until I realized that the question was actually very simple. All of the information needed to solve the problem was given, and for A) all I had to do was plug the number (-5) into 150 – 10 (-5) and I was easily able to get the answer of 200 cups. Completing B), C), and D) were Just as easy as (A) because I simply needed to understand simple concepts or plug in more numbers. There have been many similar questions to this in previous work I have done and my teacher has shown us how to do problems like this so because I pay attention in class this was not too hard for me. While working on this problem I was relaxed because once I completed a part of it I would check my answer in the answer key and I got it correct each time first try. I would definitely feel comfortable doing more problems like this, because all you need to do is plug the numbers they give you into the equation and you will get the answer. I plan on studying for this unit by always doing my homework questions, and completing the practice test. Over all I thought that this question was pretty easy and I felt very comfortable with it.

Question #3 Page 479 (ANSWERED):

A) Determine the value of N(-5)

N(-5) = 150 – 10(-5)

N(-5) = 200

B) Write in words the meaning of N(-5)

200 cups of hot chocolate were sold when the temperature was -5 degrees celcius

C) what was the average temperature if 190 cups of hot chocolate were sold

190(T) = 150 – 10(T)

190 – 150 (T) = 150 – 150 – 10(T)

40(T) = -10(T)

40(T) / -10(T) = -4

The average temperature was -4 degrees celcius.

D) Explain how to estimate the lower limit of the domain of the relation

To estimate the lower limit of the domain you would just need to estimate the minimum average daily temperature.

By Trevor Thirsk