A young girl gives her toboggan a push of 4.0m/s uphill. It slides up the hill slowing down at an acceleration of 8.0m/s down. It comes to a stop and then slides back towards her speeding up at the same rate as it slowed down on the way up. If the girl has to run 48m down the hill from where it first was pushed to get to where her sled stopped , find the elapsed time for the journey