Answer:
(b) 67
Step-by-step explanation:
A solution to the differential equation describing the temperature according to Newton's Law of Cooling could be written as ...
T = (final temp) + (initial difference)×(decay factor)^t
where the decay factor is the fraction of change during 1 unit of time period t.
__
Here, the initial difference of 100-25 = 75 degrees decays to 90-25 = 65 degrees in 1 minute. So, the units of t are minutes, the decay factor is 65/75, the initial difference is 75 degrees, and the final temperature is 25 degrees. That lets us write the equation as ...
T = 25 +75(65/75)^t
Then for t=4, the temperature is ...
T = 25 +75(13/15)^4 ≈ 67.3 . . . . degrees
After 4 minutes the temperature of the coffee is about 67 degrees.
14/16 or anything like that
If you would like to solve (- 0.5) / (- 0.5) and - 50 / (- 0.5), you can do this using the following few steps:
(- 0.5) / (- 0.5) = 0.5 / 0.5 = 1
- 50 / (- 0.5<span>) = 50 / 0.5 = 50 / (5/10) = 50 / (1/2) = 50 * 2/1 = 100
</span>
The correct results would be: (- 0.5) / (- 0.5) = 1 and - 50 / (- 0.5<span>) = 100.</span>
Answer:
<u>60+14.35=88.27</u>
Step-by-step explanation:
5x12 for the rectangle on the right, then for the circle, using the formula A=πr², I get 28.27, which you divide by 2 because you only need half of the circle, and you get 88.27. I calculated the radius by subtracting 12-6 and then dividing that in half because the radius is half of the distance to the other end of the circle. Then you get the radius of 3, then plug it into the formula to get π(3)², which is just 3.14(9), and you get 28.27.