GRE Math - Quantitative Comparison - QC Strategy - Approximation
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- Опубліковано 17 жов 2013
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Thankyou ! Finally some real stuff rather than those Commercial videos .
Such a great video and advise! Thank you!
Thanks!
Great concept
you guys are great!
Thanks Daniel!
I am enjoying learning your tricks... I am planning on barely using the calculator if not at all... Thank you..
Glad to help!
learned new things
Glad to hear!
you can also add up the numbers at the end for example 13*48 =26*24
13+48=26+24
61=50
so the Ans is A
also if there is another multiplication and comes up with same number look for small difference for example 13*48 =15*46
13+48=15+46
61=61
difference between two numbers 35=31
smaller the difference bigger the multiplication number so the Ans is B in second one
Your strategy of turning the products 13x48 and 26x24 into the sums 13+48 and 26+24 will not always give you the correct answer.
Consider this example:
QUANTITY A: 13 x 2 = 26
QUANTITY B: 6 x 6 = 36
Here, the product in Quantity B is greater than Quantity A.
However, if we convert the quantities to sums, we get:
QUANTITY A: 13 + 2
= 15
QUANTITY B: 6 + 6
= 12
Here, the sum in Quantity A is greater than Quantity B.
a-wesome
your video are awesome, but seriously yours last with A X B = 2a x 1/2B is not realistic at all; it require that you see quickly one of the term is half or double of the others which not necessary obvious when you start the exercise. But to sum up you did a good job. I am preparing my GRE and until you are the best in this subject on youtube
www.filingdoc.com by Oak&Eagle Multi services The technique if of the most value when one of the values ends in 5. Numbers ending in 5 are very easy to double and the result is a much easier number to work with.
Dumb question but why did he only use AxB=2A x 1/2 B on part A but not part B?
either part would work
How about I directly multiply 2.5*2.3=5.75 & 1.3*4.8=6.24; I am directly and quickly getting the answer... please let me know if I am wrong. Thanks!
That's fine, but it would be more appropriate to round 259,598 to 2.6 and round 238,774 to 2.4 (rather than 2.5 and 2.3 as you have done)
Hello, In the example where we have chosen A*B strategy, can it be compared using digital root technic as well? I got 6 for column A and 4 for column B and hence A>B. Please confirm. Thanks.
Sorry, I'm not sure what you're asking. Can explain your steps? I'm not familiar with that technique.
Sure. Following is my technic:
For 131,047*480,111 we can calculate digital root by adding the digits. 1+3+1+0+4+7 = 16 ;
1+6= 7
Similarly, 4+8+0+1+1+1 = 15;
1+5=6
Now, simply calculate, 7*6 = 42;
4+2= 6 {as digital root is always a single digit value}
Performing the same for column B, we get 4 as a digital root and now compare the quantities.
I deeply appreciate your playlist and I have thoroughly studied each and every video as per the instructions. Once again Thank you for that!!
@ 3:20 how do we know that 123/250 is close to 1/2 without using calculators??
We might recognize that 125/250 = 1/2
So, 123/250 must be close to 1/2
But you're provided with a calculator
MilitanT07 That's true. But it's an ONLINE calculator which is time consuming to use. We can solve this question much faster if we use some approximation techniques.