Merkle Graduate PPC Marketiing Scheme interview questions

Two days after sending in my CV I was asked to complete an online interview. This consisted of 7 questions, most of which were to do with my A Level and Degree choices and required an immediate response. However, the questions on why I was interested in PPC, and on how search engines ranked ads gave you 30 seconds to prepare. I prepared well for these questions and gave detailed answers but was informed a few days later that I had been unsuccessful. No feedback given about how I could have improved.