Answer:
y=kx
subst y=10 and x=20 into the above
<em>1</em><em>0</em><em>=</em><em>k20</em>
<em>k</em><em>=</em><em>1</em><em>0</em><em>/</em><em>2</em><em>0</em>
<em>k</em><em>=</em><em>1</em><em>/</em><em>2</em>
<em>therefore</em><em> </em><em>relationship</em><em>:</em><em> </em><em>y</em><em>=</em><em>1</em><em>/</em><em>2</em><em>x</em>
<em>subst</em><em> </em><em>x</em><em>=</em><em>1</em><em>5</em><em> </em><em>into</em><em> </em><em>the</em><em> </em><em>relationship</em>
<em> </em><em>y</em><em>=</em><em>1</em><em>/</em><em>2</em><em>(</em><em>1</em><em>5</em><em>)</em>
<em>y</em><em>=</em><em>7</em><em>,</em><em>5</em>
Step by step explanation:
- Step 1: when they say y varies directly with x they mean<em> y is proportional to x</em>
- step 2: so y=kx where <em>k is the constant</em>
- step 3: is to substitute <em>y=10</em> and <em>x=20</em> into the above equation y=kx
- step 4: you will end up with <em>10=k20</em> then divide both sides by 20 so that <em>k becomes the subject of the formula </em>
- step 5: your answer from the above will be <em>k=10/20 </em>so the relationship is <em>y is directly proportional to 1/2 x </em>what you did here is that you substituted k for 1/2 in the equation in step 3
- step 6: is to finally substitute x=15 into the equation <em>y=1/2x</em> to finally get your answer <em>y</em><em>=</em><em>7</em><em>,</em><em>5</em><em>.</em>
Answer:
45.50° F
Step-by-step explanation:
As per Newton's law,

When T(t) is the final temperature
= Temperature of surrounding
= Initial temperature
t =duration of cooling
k = constant


Now take natural log on both the sides



4.6347 - 5.0434 = -5k

k = 0.0817

= 
= 155 (02935)
= 45.49 ≈ 45.50° F
Well I don't know if I would recommend the blue I would actually would go for the yellow because it is my favorite color so ya she should pick yellow.
Answer:
It's true, if that's what your asking.
Step-by-step explanation:
5/6 = 0.833 to 3 sig.fig.
4/5 = 0.800 to 3 sig.fig.
6/7 = 0.857 to 3 sig.fig.
0.833 is more than 0.800 and less than 0.857.
The formula to find the surface area of a sphere is A=4(3.14)r². So if you plug in the data you would get,
A=4(3.14)4²
A=(12.56) (16)
A=200.96
You mught want to check over it so you will be able to solve it for yourself the next time you have this question.