When Gisela starts running, Kim is walking and is 10 yards ahead of her. Moving in the same direction on the same straight path, Gisela runs 5 yards for every 1 yard that Kim walks. At these relative rates, how many yards will Gisela have to run in order to catch up with Kim? Question from October 2015, I did not know how to approach it adequately, so I just tried to approximate and guessed 11.5, which was note the answer (A. 2.5, B. 7.5, C. 11,5, D. 12.5, E. 13.0)

See here, from the other Q&A. Man, it’s weird to have two Q&As…