Xiao Ming walked 40 meters to the east for the first time, 30 meters to the west for the second time, and 40 meters to the west for the third time. How many meters west is Xiao Ming’s position relative to the starting point
小明第一次向东走40米，第二次向西走30米，第三次向西走40米，最后小明相对起点的位置是西多少米处
<result>30</result>