讲解一下这条题目并解答---```plain text **Question Number:** 20 **Problem Description:** Xiaoming has 10 black cards and 10 white cards, each set numbered from 0 to 9. He shuffles them like playing cards, face down, and arranges them in four rows according to the following rules: **Arrangement Rules:** 1. Arranged from left to right in ascending order. 2. When black and white cards have the same number, the black card is placed on the left. Xiaoming has turned over some cards, as shown in the figure: **Diagram Description:** The diagram shows four rows of cards. Each row contains 5 cards. Cards are represented by squares. Filled squares represent black cards, and unfilled squares represent white cards. Numbers are shown on the revealed cards. * **Row 1:** An unfilled square (white card), a filled square with "5" (black card), an unfilled square (white card), a filled square (black card), an unfilled square with "9" (white card). * **Row 2:** An unfilled square with "1" (white card), a filled square (black card), an unfilled square (white card), a filled square (black card), an unfilled square with "5" (white card). * **Row 3:** An unfilled square with "0" (white card), a filled square (black card), an unfilled square (white card), a filled square with "7" (black card), an unfilled square (white card). * **Row 4:** A filled square with "2" (black card), an unfilled square (white card), a filled square (black card), a filled square with "8" (black card), an unfilled square (white card). **Additional Text:** Based on the arrangement rules, Xiaoming can deduce the numbers on the remaining cards. Some card numbers can be uniquely determined, while others cannot be uniquely determined. **Questions:** (1) Find the number on the last white card in the fourth row. (2) Xiaoming guesses the numbers on the cards that cannot be uniquely determined. What is the probability that Xiaoming guesses all the numbers correctly in one attempt? ```