Hi Brent,
I have a few questions, so I start with the first one. In the video 38 of Integer Properties module, we have a DS q. You don't rule out the first statement because you say 5J should have prime factorization of 5*?*?*?*?, and 3k should have prime factorization of 3*?*?*?*?. And since the first statement says that GCD of 5k and 3J is 30, we know that they both should have a 5*3*2 common in their prime factorization. And when we divide 5K by 5 and 3J by 3, we would have K=2*3*?*? and J=2*5*?*?. And we know that none of the prime factors in place of question marks should be common between K and J (otherwise GCD of 5K and 3J wouldn't be 30). So now the GCD of K and J is 2. So you conclude that statement 1 is sufficient to answer the question since it gives us only one GCD. However, what if 5K's prime factorization was like this: "5*2*3*5", and 3J's prime factorization was like this: "3*2*5*3". As we can see they still have the GCD of 30. And when we divide 5k by 5 and 3J by 3, we would have K=2*3*5 and J=2*3*5. So their GCD is 30 now! So I think as you rule out the second statement by saying that 2K may or may not have a 2 in its prime factorization, I suppose we can say the same thing for the statement 1 about 5K and 3J. So I thought we should have ruled out the first statement as well since it can give us more than one answer, hence E. Am I making a mistake here? What am I missing?
My second question is about the number of RC questions that accompany a passage on the GMAT. In the first video of RC module, you mention that short passages TYPICALLY get 3 questions, and long passages TYPICALLY get 4 questions. But on the Official Guide (13 ed.), for example, we have questions 75,76,77,78,79,80,81,82, and 83 all for one passage (we have a lot of series of 6,7, or 8 questions that are asked from one passage on the OG 13). So I was wondering if on test day I may have a RC passage followed by 6,7,8, or 9 qs. Sorry if this question is a little bit naive. I tried to see if I can find a post that asks the same thing in RC forum.
And my last question is a little bit out of scope of this forum, but I'll ask it anyway. I received all the 60 emails of The 60-Day GMAT Study Guide of BTG a year ago (in July, so it has Integrated Reasoning days). However, I am now using these emails as my GMAT study plan. So I was wondering if you have made any modifications on these emails or if you have changed something. If so, please let me know, because I would like to know those even little changes that you might have made on this 60-day guide, so I can follow the updated 60-day BTG guide. Thanks a lot in advance.
I have a few questions, so I start with the first one. In the video 38 of Integer Properties module, we have a DS q. You don't rule out the first statement because you say 5J should have prime factorization of 5*?*?*?*?, and 3k should have prime factorization of 3*?*?*?*?. And since the first statement says that GCD of 5k and 3J is 30, we know that they both should have a 5*3*2 common in their prime factorization. And when we divide 5K by 5 and 3J by 3, we would have K=2*3*?*? and J=2*5*?*?. And we know that none of the prime factors in place of question marks should be common between K and J (otherwise GCD of 5K and 3J wouldn't be 30). So now the GCD of K and J is 2. So you conclude that statement 1 is sufficient to answer the question since it gives us only one GCD. However, what if 5K's prime factorization was like this: "5*2*3*5", and 3J's prime factorization was like this: "3*2*5*3". As we can see they still have the GCD of 30. And when we divide 5k by 5 and 3J by 3, we would have K=2*3*5 and J=2*3*5. So their GCD is 30 now! So I think as you rule out the second statement by saying that 2K may or may not have a 2 in its prime factorization, I suppose we can say the same thing for the statement 1 about 5K and 3J. So I thought we should have ruled out the first statement as well since it can give us more than one answer, hence E. Am I making a mistake here? What am I missing?
My second question is about the number of RC questions that accompany a passage on the GMAT. In the first video of RC module, you mention that short passages TYPICALLY get 3 questions, and long passages TYPICALLY get 4 questions. But on the Official Guide (13 ed.), for example, we have questions 75,76,77,78,79,80,81,82, and 83 all for one passage (we have a lot of series of 6,7, or 8 questions that are asked from one passage on the OG 13). So I was wondering if on test day I may have a RC passage followed by 6,7,8, or 9 qs. Sorry if this question is a little bit naive. I tried to see if I can find a post that asks the same thing in RC forum.
And my last question is a little bit out of scope of this forum, but I'll ask it anyway. I received all the 60 emails of The 60-Day GMAT Study Guide of BTG a year ago (in July, so it has Integrated Reasoning days). However, I am now using these emails as my GMAT study plan. So I was wondering if you have made any modifications on these emails or if you have changed something. If so, please let me know, because I would like to know those even little changes that you might have made on this 60-day guide, so I can follow the updated 60-day BTG guide. Thanks a lot in advance.
