Answer as many as you can please!!

21. How many nine-digit security numbers are available if the only restriction is that the number 000-00-0000 cannot be assigned? 20. How many different outfits consisting of a shirt and a tie can be chosen from seven shirts and five ties? 19. How many 6-letter code symbols can be formed from the letters from the word PLANTS without repetition? 16. How many different possibilities are there for 30 athletes to win first, second, and third places? 15. One hundred college students were surveyed after voting in an election involving a Democrat and a Republican. Fifty were first-year students, 60 voted Democratic, and 25 were non-first-year students who voted Republican. How many first-year students voted Democratic 14. A merchant surveyed 290 people to determine the way they learned about an upcoming sale. The survey showed that 130 learned about the sale from the radio, 120 from television, 160 from the newspaper, 70 from radio and television, 50 from radio and newspapers,40 from television and newspapers, and 10 from all three sources. How many people learned of the sale from radio or television but not the newspaper? 12. A merchant surveyed 390 people to determine the way they learned about an upcoming sale. The survey showed that 200 learned about the sale from the radio, 180 from television, 160 from the newspaper, 120 from radio and television, 100 from radio and newspapers, 70 from television and newspapers, and 60 from all three sources. How many people learned of the sale from newspapers or radio, but not both? 11. Of the 173 students who took a mathematics exam, 99 correctly answered the first question, 79 correctly answered the second question, and 49 correctly answered both questions. How many students answered the second question correctly, but not the first Tho. Of the 136 students who took a mathematics exam, 60 correctly answered the first question, 67 correctly answered the second question, and 31 correctly answered both questions. How many students did not answer either of the two questions correctly