1. On 10% of the days, Sam's computer does not work. If the computer does not work, then he turns on the television, and independently of the computer, on 30% of the days he finds nothing interesting on television. If he finds nothing interesting on television, he calls his wife at work. Independently of television programming and the computer, on 75% of all occasions she does not pick up the phone. In that case, Sam goes to bed at 8W00 PM. On what percentage of days does Sam go to bed at 8W00 PM?
2. What is the probability that four cards drawn at random from a deck of cards are of different denominations if they are of different suits?
3. In an urn, there are three black balls, four green balls, and five red balls. Two balls are randomly drawn from the urn and are found to be of the same color. What is the probability that they are both red?