A pipeline is to be constructed to connect a point P on the shore of one side of a straight river to a point Q which is located on the shore on the other side of the river and 127 metres down the river. The cost per meter of constructing the pipeline over was is 3 times the cost of constructing the pipeline over land. The plan is to run the pipeline from point P along the shore x metres and then cross the river at an angle so as to connect directly to point Q. The river is 49 metres wide. For what choice of distance x is the cost minimum