Answer:
The time is 135 min.
Step-by-step explanation:
For this situation we are going to use Newton's Law of Cooling.
Newton’s Law of Cooling states that the rate of temperature of the body is proportional to the difference between the temperature of the body and that of the surrounding medium and is given by

where,
C = surrounding temp
= temp at any given time
t = time
= initial temp of the heated object
k = constant
From the information given we know that:
- Initial temp of the cake is 310 °F.
- The surrounding temp is 72 °F.
- After 30 minutes the cake's temperature is 220 °F.
We want to find the time, in minutes, since the cake's removal from the oven, at which its temperature will be 100°F.
To do this, first, we need to find the value of k.
Using the information given,


Next, we find the time at which the cake's temperature will be 100°F.

By definition, the span of two vectors is the set of all possible linear combinations of said vectors. So, any element in W is obtaining by choosing two numbers a,b and building

(a)
So, you can show a nonzero polynomial in W by choosing any values of a and b, as long as they're not both zero. To keep it as simple as possible, we can choose for example a=1, b=0 and we obtain one of the base vectors of W:

(b)
Factoring the powers of x, we see that a generic polynomial in W looks like

So, we must build a polynomial

such that it is not possible that

For example, let's try the polynomial 
We should solve the system

And you can check that it has no solutions. So, the polynomial
does not belong to W. On the other hand, it surely belongs to V, because it is a polynomial with degree less than 3. So, the polynomial
belongs to V/W.
First you need to divide 70 by 2 in order to cut it in half which would give you 35. Then add 27.50 and you get 62.5. Subtract that from 70 and you get 7.50 so he saved $7.50 each month
Answer:
2
Step-by-step explanation:
6-4 over 2-1
2 over 1
=2
I hope this is correct and have a great day
Answer:
9 months
Step-by-step explanation:200+30m=470
30m=270
m=9
He will pay for 9 months