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What is the probability that the product of two integers (no
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06 May 2019, 04:41
06 May 2019, 04:41
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What is the probability that the product of two integers (not necessarily different integers) randomly selected from the numbers 1 through 20, inclusive, is odd?
(A) \(0\)
(B) \(\frac{1}{4}\)
(C) \(\frac{1}{2}\)
(D) \(\frac{2}{3}\)
(E) \(\frac{3}{4}\)
(A) \(0\)
(B) \(\frac{1}{4}\)
(C) \(\frac{1}{2}\)
(D) \(\frac{2}{3}\)
(E) \(\frac{3}{4}\)
Re: What is the probability that the product of two integers (no
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13 Oct 2019, 02:14
13 Oct 2019, 02:14
Consider the numbers: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
In order to get an odd number out of a multiplication we need to multiply two odd numbers.
On the list above we count 10 odd and 10 even numbers, so the probability to pick one odd is 10/20 = 1/2.
Since repetition is allowed, then also the second number has a probability of 1/2.
Therefore, 1/2 * 1/2 = 1/4.
The answer is B.
In order to get an odd number out of a multiplication we need to multiply two odd numbers.
On the list above we count 10 odd and 10 even numbers, so the probability to pick one odd is 10/20 = 1/2.
Since repetition is allowed, then also the second number has a probability of 1/2.
Therefore, 1/2 * 1/2 = 1/4.
The answer is B.
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Re: What is the probability that the product of two integers (no
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02 Feb 2021, 04:21
02 Feb 2021, 04:21
sal60 wrote:
Consider the numbers: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
In order to get an odd number out of a multiplication we need to multiply two odd numbers.
On the list above we count 10 odd and 10 even numbers, so the probability to pick one odd is 10/20 = 1/2.
Since repetition is allowed, then also the second number has a probability of 1/2.
Therefore, 1/2 * 1/2 = 1/4.
The answer is B.
In order to get an odd number out of a multiplication we need to multiply two odd numbers.
On the list above we count 10 odd and 10 even numbers, so the probability to pick one odd is 10/20 = 1/2.
Since repetition is allowed, then also the second number has a probability of 1/2.
Therefore, 1/2 * 1/2 = 1/4.
The answer is B.
What if both the integers are different? We need to take that case in account as well!
