Logan, Cassie and Abbey are doing the Pulse Speed Lab. Logan and Cassie stand 7.86 m apart and stretch a zinc-coiled snakey between them. Logan introduces a pulse into the snakey at his end. Using a stopwatch, Abbey measures that it takes 14.9 seconds for the pulse to travel to Cassie's end and back two times. They then repeat the experiment with a copper-coiled snakey stretched the same distance and find that pulses travel back and forth two times in 17.2 seconds. Determine the speed of the pulse in the copper-coiled snakey.