There are 50 balls of exactly the same size and shape in a bag, including 10 red balls, 10 green balls, 10 yellow balls, 10 blue balls, and the rest are white and black. If you want to ensure that 7 balls of the same color are taken out, at least how many balls must be taken.
一只布袋里有50只大小形状完全一样的球，其中红色的球10只，绿色的球10只，黄色的球10只，蓝色的球10只，其余的是白色的和黑色的球．如果要确保取出同样颜色的球7只，至少要取多少只球．
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">24 + 10 + 1</gadget>
<output>35</output>

<result>35</result>