An explorer was walking through the desert. One day he set up his tent, took out a compass and looked eastward for a light source of water. After walking 2 kilometers, he found no source of water. Later, he found that the source of water needed to be relocated due to a change of reference, so he went to After walking -3.5 kilometers east, I finally found the water source. May I ask what direction the water source is at the campsite? How far is it from the campsite?
一个探险家在沙漠中穿行，一天他扎好帐篷，拿出指南针轻装向东寻找水源，走了2千米，没有发现水源，后来发现由于参照物改变了，需要重新定位水源地，于是又向东走了-3.5千米，终于找到了水源．请问水源地在宿营地的什么方向？距宿营地有多远？
<result>1.5</result>