There are two points B and C on line segment AD, satisfying AC=(1/2)AD, AB=(1/3)AC, if AB+AC+AD=50cm, find the length of line segment BC.
线段AD上有两点B，C，满足AC=(1/2)AD，AB=(1/3)AC，若AB+AC+AD=50cm，求线段BC的长．
<gadget id="calculator">1 + 3 + 6</gadget>
<output>10</output>

<gadget id="calculator">50 / 10</gadget>
<output>5</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<result>10</result>