10封不同的信，投到3个相同的邮筒中，若一个邮筒力投2封信，另外两个邮筒各投4封信，不同的投法种数是 未知类型：{'options': ['[tex=3.357x1.5]U4X94MgA6zMWbfa0+266d2tW2FfleDP9MyNIH8qEtBtyYdHy+IQ9wX2+HWrcnwrRnqcri2HUFgUD+iFWU2RdXw==[/tex]', '[tex=4.857x1.5]U4X94MgA6zMWbfa0+266d2tW2FfleDP9MyNIH8qEtBtyYdHy+IQ9wX2+HWrcnwrR+IoaQjhhSesyBvXBS9MmSxVxV3MQ4LlSkDtBx28xIwY=[/tex]', '[tex=3.786x2.5]bMsKSIG15bYxMMope6rKDqvInMcCW1ea2HXppkZCUehdP+5/l7htqUUd9fHw/RQL[/tex]', '[tex=3.571x2.571]mbD30EcAE6dNglFnTEo9xQ0bMM20svOsXLecSvbNj3pHzMlkjA6+KXw2wsQCjLBlznubKSbzwGBz+5fNzwCi6FhKcclXoms3XP/4hyMiCe8=[/tex]', '[tex=4.857x1.5]U4X94MgA6zMWbfa0+266d2tW2FfleDP9MyNIH8qEtBtyYdHy+IQ9wX2+HWrcnwrR+IoaQjhhSesyBvXBS9MmS3X6sBv0ep12+V2WsCL4kC4=[/tex]'], 'type': 102}