There are 15 balls of each color black, white and red. Mix it in a bag, and take at least a few out of it. In order to ensure that 6 of the drawn balls are of the same color, at least how many should be drawn.
黑、白、红三种颜色的小球各有15个．混合放在袋子中，从中至少摸出若干个．为了保证摸出的球中有6个是同色的，至少应摸出多少个．
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">15 + 1</gadget>
<output>16</output>

<result>16</result>