An express train and a local train run from a and B at the same time and meet each other 4 hours later. It is known that it takes 7 hours for the express train to complete the whole journey, 17 kilometers more than the local train per hour. How many kilometers can the express train run per hour?

An express train and a local train run from a and B at the same time and meet each other 4 hours later. It is known that it takes 7 hours for the express train to complete the whole journey, 17 kilometers more than the local train per hour. How many kilometers can the express train run per hour?

If the express train runs x kilometers per hour, the slow train runs x-17 kilometers per hour, so 4x + 4 (x-17) = 7x & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 8x-68 = 7x & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 68 A: the express train runs 68 kilometers per hour