Answer:
The answer is "
"
Step-by-step explanation:
Given:

Find critical points:

differentiate the value with respect of x:
critical points
![\to (x-e)^2 e^{(e-x)} [e+3-x]=0\\\\\to e^{(e-x)}\neq 0 \\\\\to (x-e)^2=0\\\\ \to [e+3-x]=0\\\\\to x=e\\\\\to x=e+3\\\\\to x= e,e+3](https://tex.z-dn.net/?f=%5Cto%20%28x-e%29%5E2%20e%5E%7B%28e-x%29%7D%20%5Be%2B3-x%5D%3D0%5C%5C%5C%5C%5Cto%20e%5E%7B%28e-x%29%7D%5Cneq%200%20%5C%5C%5C%5C%5Cto%20%28x-e%29%5E2%3D0%5C%5C%5C%5C%20%5Cto%20%5Be%2B3-x%5D%3D0%5C%5C%5C%5C%5Cto%20x%3De%5C%5C%5C%5C%5Cto%20x%3De%2B3%5C%5C%5C%5C%5Cto%20x%3D%20e%2Ce%2B3)
So,
The critical points of 
The proportionality constant "k" is 1.88
<h3><u>Solution:</u></h3>
Given that y varies directly with x
y = 15 when x = 8
To find: proportionality constant "k"
Direct variation means that increase/decrease in one quantity also causes increase/decrease in other quantity.
⇒ y varies directly with x
This means,

Can also be written as:
y = kx
Where "k" is the proportionality constant
Substituting the given values of "x" and "y"
15 = k(8)

k = 1.875
On rounding to nearest hundredths place we get 1.88
Thus the proportionality constant is 1.88