Answer: B 1/3
Step-by-step explanation:
For every 3x it travels 1 y so you will get 1/3 as your answer.
At 50y the line is at 10x. By the time it is at 60 y it is at 40x. This was a change in y by 10 and change in x by 30. There fore the answer is 10/30 or 1/3.