Whose orange juice mixture is stronger

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

700 miles the train takes 5 hours to a travel the distance at what unit rate is the train traveling?

Arectangle plot measure 20ft. by 30ft. a 3-ft.-wide sidewalk surrounds it. find the area of the sidewalk.