9, 16, x which should be the right answer
The answer above is mostly correct, HOWEVER The ellipse is a vertical ellipse and therefore uses the equation (x^2/b^2)+(y^2/a^2)=1
a=10/2=5
b=8/2=4
put it in the equation and it is (x^2/4^2)+(y^2/5^2)=1
Simplify and the answer is (x^2/16)+(y^2/25)=1
50%
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The pic below shows the process.
The way I did this was determine the proofreaders’ page/hour rate. 200/6 is 33.33, while 200/9 is 22.22. 55.55 in total. 55.55/hour, combined, means that this hourly rate would need to multiply to fit in three hours. Thus, we multiply 55.55 by three, giving us 166.65. This is not two hundred, meaning you need more time, or better proofreaders.