Two objects of mass 10 kg and 20 kg respectively are connected to the two ends of a rigid rod of length 10 m with negligible mass. The distance of the center of mass of the system from the 10 kg mass is :
(1) 10 m
(2) 5 m
(3) $10 \over 3$ m
(4) $20 \over 3$ m
(1) 10 m
(2) 5 m
(3) $10 \over 3$ m
(4) $20 \over 3$ m