Three point masses lie along the x-axis: 1kg at x=0m, 2kg at x=2m, and 4kg at x=5m. The 2kg mass is suddenly removed from the system without disturbing the other two masses. What is the new x-coordinate of the center of mass of the remaining system?
a) 2.5m
b) 3.5m
c) 4.0m
d) 4.8m