This is a great question, Atharva! Honestly... it depends. If you're not sure how to approach the problem after ~30 seconds and you're slammed for time, this would be a great candidate to guess on. But if you've got the approach figured out and you're on target for time, it's reasonable for some Quant problems to take ~3 minutes! I typically think about Quant problems as taking between 1 and 3 minutes, with the shorter ones balancing out the longer ones to give 2 minutes per question on average. This would be one of the longer ones for sure. That said, I wouldn't take more than 3 minutes on a Quant problem - it just isn't worth it.
Can you please make more videos on permutations and combinations.. the differences and how to distinguish the problems with respect to which concept would be used in which case
Questions that include words like, "arrangement," "display," "rank," or "order" are indicative of a permutation's question. Problems that ask about the number of ways you can combine, or create subgroups signal a combination's question.
4:41 what is BC? the answer is 2 , 'statement 2 alone is sufficient to answer the question but statement one alone is not sufficient. one you chose this answer, you cannot choose the other choices since it contradicts the other 4 choices 1. you can't answer this question alone (all degrees) with statement one 2 yes you can answer the question with statement 2 alone since it is 90, 60, 30 degree triangle and in this instance BC=1 since AD=1 and since BC is one-half the length of AC and BC is one-half AC
9:22 Since the expression a/b + 1 can be expressed as (a+b)/c and since each unknown is one of the numbers 2, 3, or 5, you want the ----------- c/b denominator to be the smallest (2)of the three integers, hence (3 + 5)/2 = 4 . Hence the greatest possible value o expression is 4, answer
13:17 answer 17 A A B x B ----------- C B 5 B Only 1x1, 5x5, 6x6 will give you the same digit B B B 1 can be ruled out since 1 would give AAB (and not four digits CB5B), 5 can be also ruled out since 5 x a number 'n' would have to equal 3 (but 5 times a number 'n' equals 0 or 5). Hence B is 6. Need A to be number when multiplied by B (which is 6) will give 2 (either 6x7 or 2x 6). A is 7 hence 7 7 6 x 6- = 4 6 5 6 Hence A+B+C = 17 answer
For the hard arithmetics problem isn't B surely 6? I crossed out 5 because it was a known value in the answer (CB5B) where it would just be shown as B instead of 5. I am new to GMAT, so please correct me if I'm wrong. Thanks!
Hi Sajid! Erika showed us that for the problem we had BxB= a number that ends in B. So, she was going through the options quickly to show which ones would give us that result. Since 5x5=25, that is one option (25 ends in 5). And since 6x6=36, that is another option (36 ends in 6). Then, Erika began by plugging the 5 in for B in the problem. However, when she saw that 5A would have to equal a number that ends in 3, she could tell it wouldn't work out because no integer multiplied by 5 ends in 3. So, that's how she determined B = 6. Hope this helps a bit! Happy studying to you! :D
Question that starts after 12:14: How can one assume it's B*B that resulted in 4 digit number, even if it was giving other product something to carry, the 4 digit number might be because of B*A.
In this case the only number we ruled out due to that issue was 1, and that's because it is not possibly to multiply a 3-digit number by 1 and get a 4-digit result. For example, 311 * 1 = 311. That will always be the case, and no numbers will carry over since the highest number, 9, multiplied by 1 is still 9. You won't get a result big enough that it needs carried. Hope that helps!
15:45 , B cant be 5 since A would have to be a unit digit that when multiplied by 5 = 3, but 5 times any number ends in either 0 or 5, hence A =5 has to be ruled out hence A =6
1:15 angle E =45 since angle DAE =40 (parallel line and transversal) given that angle C from ACB =40 (75+65+40=180) hence 180- (40+95)=45 degree answer
