The answer is 7/5. I attached the work below.
The answer is 21 because 189 divided by 9 is 21
Equation of a circle in standard form:
(x-h)²+(y-k)²=r²
r=radius
(h,k) is the center.
In this case:
(h,k) =(0,0) (h=0,k=0 )
r=4
Therefore:
(x-0)²+(y-0)²=4²
x²+y²=16
Answer: x²+y²=16
Let
x--------> the number of children
y------> the number of teenagers
z------> the number of adults
we know that
------> equation A
-----> equation B

-------> equation C
Substitute equation C in equation A and equation B
![2[\frac{4}{3}y]+3y+5z=1,950](https://tex.z-dn.net/?f=2%5B%5Cfrac%7B4%7D%7B3%7Dy%5D%2B3y%2B5z%3D1%2C950)
--------> equation D
![[\frac{4}{3}y]+y+z=570](https://tex.z-dn.net/?f=%5B%5Cfrac%7B4%7D%7B3%7Dy%5D%2By%2Bz%3D570)
--------> equation E
Multiply equation E by 
--------> equation F
Adds equation D and equation F

therefore
<u>the answer is the option</u>
