3. Pete sets up 12 hurdles for a race that is 600 metres long. The distance between the starting line and the first hurdle is 50 metres. The distance between the last hurdle and the finishing line is 55 metres. The distance between each pair of consecutive hurdles is $d$ metres. What is the value of $d$ ?
3. Since there are 12 hurdles, then there are 11 gaps between the hurdles, each of length $d$ metres. The gap before the first hurdle is 50 metres and the gap after the last hurdle is 55 metres. Since the race is 600 metres long, then $50+11 d+55=600$ or $11 d=495$ and so $d=45$.
ANSWER: $d=45$