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
we will pick new questions that match your level based on your Timer History
Track Your Progress
every week, we’ll send you an estimated GMAT score based on your performance
Practice Pays
we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
We will open up GMAT Club Tests this weekend to be used freely without a subscription on Saturday at 00:01 and will keep them open through Sunday 23:59, US Pacific Standard Time.
Want to score 90 percentile or higher on GMAT CR? Attend this free webinar to learn how to pre-think assumptions and solve the most challenging questions in less than 2 minutes.
Sign up or for Target Test Prep’s weekly Quant webinar series. The free weekly webinar covers sophisticated, yet easy-to-deploy, tactics and strategies for handling commonly misunderstood, high-value GMAT quant problems.
Enter The Economist GMAT Tutor’s Brightest Minds competition – it’s completely free! All you have to do is take our online GMAT simulation test and put your mind to the test. Are you ready? This competition closes on December 13th.
Re: If a and b are both factors of 50, which of the following must be true
[#permalink]
Show Tags
09 Sep 2019, 21:53
1
We are informed that a and b are factors of 50. We are to determine which of the answer choices must be true. factors of 50 are {1,2,5,10,25,50}. In A, we are given that ab≥2. This is not always true for the situation a=b=1, where ab=1. In B, a+b≤50. This also not always true for the situation a=25, and b=50, whereby a+b=75. In C, ab is factor of 100. This not always true for a=10 and b=25, where ab=250. In E, ab is even. This is not necessary true for a=1, and b=5, where ab=5, which is not even. In D, ab is a factor of 2500. This always true since taking the highest possible values that a and be can take, a=b=50, and computing ab=2500. In this case 2500 is a factor of 2500. Hence D must be true.
Re: If a and b are both factors of 50, which of the following must be true
[#permalink]
Show Tags
10 Sep 2019, 04:09
1
Quote:
If a and b are both factors of 50, which of the following must be true?
(A) ab≥ 2 (B) a + b≤ 50 (C) ab is a factor of 100. (D) ab is a factor of 2500. (E) ab is even.
\(number.f(50)=(5^2,2)=(3)(2)=6\); and \(factors(50)=(1,50,2,25,5,10)\); \(a,b=any=(1,50,2,25,5,10)\)
(A) ab≥ 2: \(a,b=(1,1):ab=1\) false (B) a + b≤ 50: \(a,b=(50,50):ab=2500\) false (C) ab is a factor of 100: \(a,b=(50,25):ab=1250\) false (E) ab is even: \(a,b=(1,1):ab=1\) false
Re: If a and b are both factors of 50, which of the following must be true
[#permalink]
Show Tags
10 Sep 2019, 06:25
Prime factorization results to: 50 = 10*5 = 5*2*5 Thus, factors are: 1, 2, 5, 10, 25, 50 What must be true is that ab >= 2 since smallest factors are 1 and 2. So the correct answer should be A.
Re: If a and b are both factors of 50, which of the following must be true
[#permalink]
Show Tags
10 Sep 2019, 11:37
Factors of 50 are {1, 2, 5, 10, 25, 50} Note: a & b can take same values!
(A) ab≥ 2 —> NO [(a, b) = (1, 1)] (B) a + b≤ 50 —> NO [(a,b) = (25, 50), (50, 50) etc.,] (C) ab is a factor of 100. —> NO [(a, b) = (50, 50) etc.] (D) ab is a factor of 2500. —> YES [Maximum value of ab = 50*50 = 2500, which is still a factor of 2500] (E) ab is even. —> NO [(a, b) = (1, 1), (5, 25) etc.]
If a and b are both factors of 50, which of the following must be true?
(A) ab≥ 2 (B) a + b≤ 50 (C) ab is a factor of 100. (D) ab is a factor of 2500. (E) ab is even.
Since a is a factor of 50 and b is also a factor of 50, then ab is a factor of 50 x 50 = 2500.
To eliminate the other choices,consider the factors of 50: 1, 2, 5, 10, 25, and 50. Choice A is incorrect because if a = 1 and b = 1, then ab = 1, and A is not true. Choice B is incorrect because if a = 50 and b = 10, then a + b = 60 and B is not true. Choice C is incorrect because if a = 25 and b = 10, then ab = 250, which is not a factor of 100. Choice D is true because every product of two factors of 50 is also a factor of 50 x 50 = 2500. Choice E is incorrect because if a = 1 and b = 5, then ab = 5, which is odd, so E is not true.
close
49% (01:41) correct 
