有没有比ETS的数学思路更好的解法?
有没有比ETS的数学思路更好的解法?
这是OG里面的一道题(P402)A reading list for a humanities course consists of 10 books,of which 4 arebiographies and the rest are novels.Each student is required to read aselection of 4 books from the list,including 2 or more biographies.Howmany selections of 4 books satisfy the requirements?A 90B 115C 130D 144E 195OG的官方解法太复杂了,有没有哪位有比较好的解法?