A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

A red 20-sided die, with faces marked from 1 to 20 , is rolled. The result is denoted by D1 . Then a green 20-sided die, similarly marked, is rolled. The result here is denoted by D2 . 1) What is the probability that the value 6 shows up on at least on of the rolls? P(D1=6∪D2=6) 2) What is the probability that the value 6 show up on exactly one of the rolls? P((D1=6∪D2=6)∖(D1=6∩D2=6)) 3) What is the probability (as a rational number is a/b format) that the value sum D1+D2 is 30 ? 10 ? 23 ? P(D1+D2=30) P(D1+D2=10) P(D1+D2=23)

  • This Question is Closed
  1. Jadedry
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    1) If the value 6 appears on at least one of the dice, then it would be easier to calculate the probability of 6 not appearing at all. 19/20 * 19/20 = 361/400 1- 361/400 = 39/400 2) If 6 only shows up on one of the dice, this leaves two possibilities. D1 = 6 and D2 = other, or D1 = other and D2 = 6 (19/20 * 1/20) + (1/20 * 19/20) = 38/400 3) The numbers that equal 30 together = 20 , 10 19 , 11 18 , 12 17, 13 16,14 15,15 14,16 13,17 12,18 11,19 10, 20 = 11 possibilities in each case the probability of getting those 2 numbers = 1/20 * 1/20 = 1/400 = 1/400 * 11 = 11/400 ---- For number 10 we have: 1, 9 2,8 3,7 4,6 5,5 4,6 3,7 2,8 1,9 = 9 possibilities = (1/20 * 1/20) * 9 = 9 /400 ---- For 23 = 20 , 3 19, 4 18, 5 17, 6 16, 7 15, 8 14, 9 13, 10 12, 11 11, 12 10, 13 9, 14 8, 15 7, 16 6, 17 5, 18 4, 19 3,20 = 18 possibilities repeat the steps above, you have 18/400

  2. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.