89 is the missing value your welcome
        
                    
             
        
        
        
Add the 28 and 42
then divide by 2 
there should be 35 kids in group
        
             
        
        
        
Answer:
60 degrees
Step-by-step explanation:
The angles all have to add up to 180, so you can do 

 
        
                    
             
        
        
        
You add all of them together if it’s labeled with a X.
For example, the first X is 1 hour. If it has 2 Xs it would be 2 hours, if no X is shown above, it’s zero hours. 
Answer is 12 hours.
        
             
        
        
        
(a) Take the Laplace transform of both sides:


where the transform of  comes from
 comes from
![L[ty'(t)]=-(L[y'(t)])'=-(sY(s)-y(0))'=-Y(s)-sY'(s)](https://tex.z-dn.net/?f=L%5Bty%27%28t%29%5D%3D-%28L%5By%27%28t%29%5D%29%27%3D-%28sY%28s%29-y%280%29%29%27%3D-Y%28s%29-sY%27%28s%29)
This yields the linear ODE,

Divides both sides by  :
:

Find the integrating factor:

Multiply both sides of the ODE by  :
:

The left side condenses into the derivative of a product:

Integrate both sides and solve for  :
:


(b) Taking the inverse transform of both sides gives
![y(t)=\dfrac{7t^2}2+C\,L^{-1}\left[\dfrac{e^{s^2}}{s^3}\right]](https://tex.z-dn.net/?f=y%28t%29%3D%5Cdfrac%7B7t%5E2%7D2%2BC%5C%2CL%5E%7B-1%7D%5Cleft%5B%5Cdfrac%7Be%5E%7Bs%5E2%7D%7D%7Bs%5E3%7D%5Cright%5D)
I don't know whether the remaining inverse transform can be resolved, but using the principle of superposition, we know that  is one solution to the original ODE.
 is one solution to the original ODE.

Substitute these into the ODE to see everything checks out:
