Answer:

Step-by-step explanation:
The sum is the result obtained from adding two or more values together.
The sum of <em>s</em> and <em>t</em> is the result obtained from adding <em>s</em> and <em>t</em> together.
<em>s </em>+<em> t</em>
Step-by-step explanation: graph both equations where they intersect is the answer write it like this (x,y) the x and the y should be replaced with the numbers you'll get when they intersect. So if they intersected the point where they did if the y is 1 and x is 2 then the answer is (2,1). If they don't intersect at all and are parallel then it is no solution. If your only graphing one line which you aren't in this case but if you were it would be infinitely many.
angle 5 and angle 4 are exterior angles
1 kilometer = 1000 meters
5000 meters / 1000 = 5 kilometers
5 kilometers x 2 times per day = 10 kilometers per day.
answer: D) 10 kilometers