Answer:
B
Step-by-step explanation:
Rewriting in slope-intercept form.
x - 2y = 0
Add -x on both sides.
- 2y = 0 - x
Divide both sides by -2.
y = 0/-2 - x/-2
y = 0 - - 1/2x
y = 0 + 1/2x
y = 1/2x + 0
The slope is 1/2, the y-intercept is at (0, 0).
Let's assume that Kirby walks with a speed

for a time

, and that he runs with a speed

for a time

.
The total time available for Kirby to catch the train is:

and this must be equal to the sum of the two times t1 and t2:
The distance Kirby should cover is

and this should be equal to the sum of the distances covered by walking and by running:

So we have a system of 2 equations:


If we solve the system, we find:


So, Kirby needs to run at least for 8 minutes in order to catch the train.
You multiply 8 by 15 then again by 6 so the answer is 720