<p>I am getting very depressed with the questions involving probabilities, permutations and combinations in the Barron's math level II tests, I have used up 6 of the tests and there is little improvement of my abilities on this topic. After every test I make sure I understand the concept behind the mistaken sum, and every next test I find myself making errors I could not have prevented with what I had learned earlier.

Can you refer me some good websites where I can get a grasp of permutations and combinations involving cards, coins, words, and numbers etc good enough to stand Barron's tests? I can't buy any book now because I live overseas and my test is on Nov 6.</p>

<p>P.S. I have never have studied permutations or combinations before I bought the Barron's book. In the past few days, I have exhausted some possible sources online, such as sparknotes and GMAT questions on these topics. I suppose GMAT questions were helpful, but I am just reverse engineering everything. I hope I can find something that will give a more basic guidance. Thanks for reading.</p>