A three-digit number is drawn out of the digits from 0-9.

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In summary, the probability of drawing a three-digit number without repeating digits is 7/10. The probability of drawing a three-digit number with at least one even digit is 87.5%. There are 720 different three-digit numbers that can be drawn and the expected value of a three-digit number drawn from this set of digits is 444. The probability of drawing a three-digit number that is a multiple of 5 is 1/100.
  • #1
diceyfume
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A three-digit number is drawn out of the digits from 0-9. If no repetition of digits is allowed( that is, if 0 has been drawn for the 1st digit, it cannot be used in drawing the 2nd and 3rd digits anymore), what is the probability that the number 346 be drawn?
 
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  • #2
This won't work, diceyfume.

You are obviously refusing to utilize your intellect, and are only interested in being spoonfed "answers".

I strongly advise you to quit maths, because your attitude makes you incompetent in it.
 

1. What is the probability of drawing a three-digit number that does not include any repeating digits?

The probability of drawing a three-digit number without repeating digits is 9/10 x 8/9 x 7/8 = 7/10. This is because for the first digit, there are 9 possible choices (all digits except 0), for the second digit, there are only 8 possible choices (all digits except the one already chosen), and for the third digit, there are 7 possible choices (all digits except the two already chosen).

2. What is the probability of drawing a three-digit number with at least one even digit?

The probability of drawing a three-digit number with at least one even digit is 1 - (5/10)^3 = 87.5%. This is because the probability of drawing a three-digit number without any even digits is (5/10)^3, so the complement (1 - (5/10)^3) will give us the desired probability.

3. How many different three-digit numbers can be drawn?

There are 720 different three-digit numbers that can be drawn. This is because there are 10 choices for the first digit, 10 choices for the second digit, and 10 choices for the third digit, giving us a total of 10 x 10 x 10 = 1000 possible combinations. However, since 000 is not considered a three-digit number, we have to subtract 1, giving us a total of 1000 - 1 = 999 possible combinations. But since 000 is not included, we have to subtract another 1, giving us a total of 999 - 1 = 998 possible three-digit numbers.

4. What is the expected value of a three-digit number drawn from this set of digits?

The expected value of a three-digit number drawn from this set of digits is 444. This is because the average of all possible three-digit numbers from 000 to 999 is (0+999)/2 = 499.5. However, since 000 is not included, we have to subtract 1, giving us an average of 499.5 - 1 = 498.5. But since 000 is not included, we have to subtract another 1, giving us an average of 498.5 - 1 = 497.5. However, we have to account for the fact that there are only 998 possible three-digit numbers, so the expected value is 497.5 x 998/999 = 444.

5. What is the probability of drawing a three-digit number that is a multiple of 5?

The probability of drawing a three-digit number that is a multiple of 5 is 1/10 x 1/10 x 2/10 = 1/100. This is because for the first digit, there is only 1 possible choice (5), for the second digit, there are 10 possible choices (all digits from 0-9), and for the third digit, there are 2 possible choices (0 or 5). Multiplying these probabilities gives us the desired result of 1/100.

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