Toni is at a dock on a bank of a straight river that is 1 mile wide and wants toreach the barge toll gate on the other side, so he can warn the guards about the stolengoods on an approaching barge. The toll gate is 4 miles downstream on the opposite bank,and Toni want to get there by first rowing his boat to somewhere (call it point P) on theopposite bank and then walking the remaining distance × to the toll gate. He can row at 4mph and walk at 2 mph. Express the total time 7, in terms of x, that he takes to go from thedock to the toll gate.