It’s a question because there is not value of time.
You could solve this using a proportion or just by common sense.
Proportion: 8/12 = x/126
Cross multiply: 12x = 1008
1008/12 = 84
Or the common sense route is just dividing 12 by 8 then multiplying the answer by 126. Either way, you get the same answer. Hope this helps! :)
~Ash
Changing the subject of an equation involves solving for another variable in the equation
The equation of t is 
<h3>How to change the subject of the equation</h3>
The equation is given as:
![N=\sqrt[2]{\frac{y_i-y_o}{t^2}}](https://tex.z-dn.net/?f=N%3D%5Csqrt%5B2%5D%7B%5Cfrac%7By_i-y_o%7D%7Bt%5E2%7D%7D)
Rewrite the equation as:

Evaluate the square root of t^2

Multiply both sides by t

Make t the subject, in the above equation

Hence, the equation of t is 
Read more about subject of formula at:
brainly.com/question/657646
Yes it is because 5 5/8 it’s bigger than 5 and 3/6