At 10 a.m. two trains started traveling toward each other from stations 287 miles apart. They passed each other at 1:30 p.m. the same day. If the average speed of the faster train exceeded the average speed of the slower train by 6 miles per hour. which of the following represents the speed of the faster train, in miles per hour? (DPDC-19; NWPGCL-18)