GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
What is the probability that the product of two integers (no
[#permalink]
06 May 2019, 04:41
06 May 2019, 04:41
Expert Reply
00:00
Question Stats:
83% (01:08) correct
16% (01:16) wrong based on 31 sessions
Hide Show timer Statistics
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
[#permalink]
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.
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Given Kudos: 172
Location: India
WE:Education (Education)
Re: What is the probability that the product of two integers (no
[#permalink]
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!
