+1234 You are given the 4 x 4 grid below.
(a) Find the number of ways of placing 8 counters in the squares (at most one counter per square), so that each row contains exactly two counters.
(b) Find the number of ways of placing 12 counters in the squares (at most one counter per square), so that each column contains exactly three counters.
+57 For a, you can find that you have to choose 2 from each row, making (4 choose 2)^4, which is 1296
For b, it is the same, except it is 4 choose 3, making it 4^4=256 if i am not mistaken
