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# The Ultimate Q51 Guide [Expert Level]

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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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22 Mar 2016, 17:10
In addition, the mistake type 4(A) questions related to our life are given at level of score 50-51. In a case of the question below, the answer is A if you modify the question.

(ex 3) Machine X is taken 30 minutes for preparing to work and machine Y is taken 20 minutes for warming up before driving machines. The work rate of machine X is 40 parts per 1 minute and machine Y is 30 parts per 1 minute. Is the total time taken to work including preparing time of machine X smaller than that of machine Y?

1) The total task is more than 1,200 parts.
2) The total task is less than 1,800 parts.

Therefore, when you face with questions related to real life, approach them very cautiously.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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27 Mar 2016, 00:54
As always, questions combined with the mistake type 3 and 4 are evolving and often given. The below question is recent, which also belongs to the mistake type 4(A) at level of score 50-51. You should be able to solve this type of question and know the relation between method of approach to variables and the mistake types.

(ex 1) If x and y are different prime numbers, and n is a positive integer, what is the factors’ number of x(y^n)?

1) xy=21
2) n=2

The answer is C but also B, which is a typical question at level of score 50-51. You have to be strong with a question like this. Be cautious on integer or statistics questions, which make C the answer. Especially, be aware of the word "different" when questions with factor or prime factors are given.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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30 Mar 2016, 03:50
Besides, questions trembling students like the below still have been given on exams. The below question adapts the concept of an absolute value is an length of two points. This type of question has continuously appeared since 10 years ago. Sure, as there are 3 variables, the answer is E.

(ex 3) Is |x-y|<|x-z|?
1) |y|<|z|
2) x<0

It might look simple seemingly though it can be overwhelming when you actually face it in an exam. Approach this type of question after fully comprehending the method of approach to variables.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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Updated on: 11 Apr 2016, 17:32
As always, more developed questions combined with the mistake types 3 and 4 appear on GMAT. Look at the question below. This is a very recent one, which also belongs to the mistake type 4(A) at level of score 50-51. You should be able to tackle this type of question. Be aware of a relation between the method of approach to variable and the mistake types.

(ex 1) What is the median of 5 numbers?
1) They have 5 and 15
2) 3 of them are 10 each

In this question, the answer is C but also B, which is a typical question at level of 50-51. You have to be strong with this type of question. Focus on integer or statistics questions that make C the answer.
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Originally posted by MathRevolution on 01 Apr 2016, 07:11.
Last edited by MathRevolution on 11 Apr 2016, 17:32, edited 1 time in total.
Math Revolution GMAT Instructor
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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05 Apr 2016, 05:10
As usual, developed questions combined with the mistake types 3 and 4 appear on GMAT. Let's look at the question below. This is a recent question, which also belongs to the mistake type 4(A) at level of score 50-51. You have to excel at the question like this, and also comprehend the relation between method of variable approach and the mistake types.

(ex 1) Is the range of a, b, c, and d greater than 7?
1) c-a=4, a-d=4
2) c-b=7

The answer is C but also A, which is a typical question at level of score 50-51. You should focus on integer or statistics questions that make C the answer.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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07 Apr 2016, 16:40
Also, this question is related to the mistake type 4(A). In this case, when number and ratio are given in a question, it is most likely that ratio can be the answer.

(ex 2)A certain company sells pencils in package and its sale price is not changed for a special sales period. But if the pencils’ number in one package is reduced, by what percent the unit sale price of pencils in one package increased?

1) The sale price per one package is \$8
2) The reduced number of pencils in one package is 20 percent of the original number

In this case, B which is ratio is the answer. This type of question is at level of score 50-51
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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11 Apr 2016, 17:31
As always, more developed questions combined with the mistake types 3 and 4 appear on GMAT. Look at the question below. This is a very recent one, which also belongs to the mistake type 4(A) at level of score 50-51. You should be able to tackle this type of question. Be aware of a relation between the method of approach to variable and the mistake types.

(ex 1) What is the median of 5 numbers?
1) They have 5 and 15
2) 3 of them are 10 each

In this question, the answer is C but also B, which is a typical question at level of 50-51. You have to be strong with this type of question. Focus on integer or statistics questions that make C the answer.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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15 Apr 2016, 03:55
As always, more developed questions combined with the mistake types 3 and 4 appear on GMAT. Look at the question below. This is a very recent one, which also belongs to the mistake type 4(A) at level of score 50-51. You should be able to tackle this type of question. Be aware of a relation between the method of approach to variable and the mistake types.

(ex 1) What is the median of 5 numbers?
1) They have 5 and 15
2) 3 of them are 10 each

In this question, the answer is C but also B, which is a typical question at level of 50-51. You have to be strong with this type of question. Focus on integer or statistics questions that make C the answer.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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18 Apr 2016, 16:56
Plus, this highly advance question is related to daily life. You also should be able to tackle PS questions.

There are 4 bottles with the same number balls m respectively. If balls from the only 1-st bottle are moved to the other 3 bottles and finally the ratio of the numbers of balls of the bottles is 1 to 6 to 5 to 4, does the moved balls represent in terms of m?

A. m/4 B. m/2 C. 3m/4 D. m E. 4m/5

It might seem simple though this can be very burdensome. You shouldn’t deal with PS question with disregard.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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22 Apr 2016, 17:44
In addition, integer questions are still frequently given.
Let's have a look at the question below.

(ex 5) If the first 20 positive even numbers’ sum is 420, what is the first 20 positive odd numbers’ sum?

A. 210
B. 240
C. 320
D. 360
E. 400

-> Even numbers are always bigger by 1 and there are 20 of them, which makes a difference by 20.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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26 Apr 2016, 05:23
Furthermore, the below question is an advanced question related to real life. You also have to be strong with a PS question like this.

(ex 3) one apple is 1pound per \$1. If the apple is peeled off and cored, 1/5 of the original apple's weight is off. Then the peeled and cored apple can be apple pie and 2cups of apple juice made by a blender come from such apple 1 pound. If such 3 cups of apples juice can make one apple pie, how much money it needs to make p apple pies, in dollars?

A. 2p
B. 15p/8
C. 8p/15
D. 2p/3
E. 3p/2

It might seem simple, but it can be challenging when you actually face this type of question on actual GMAT
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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29 Apr 2016, 00:13
Moreover, highly advanced integer questions are frequently given.

(ex) For positive integers n, k, f(n) is the remainder when n is divided by k. Is k>10?

1) f(k+32) = 8
2) f(k+42) = 6

In this case, the answer is B. You must have a solid concept of integer questions.
For 1), k=12,24 -> always yes and sufficient.
For 2), k=9 no, 12 yes -> not sufficient.

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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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02 May 2016, 04:03
Also, highly advance integer questions are frequently given.

We define “A mod n” as the remainder when A is divided by n. What is the value of “A mod 6”?

1) A mod 3=A mod 12
2) A mod 4=2

In this case, the answer is C. You have to have a solid concept of integer questions.
For 1), A mode 6=1,2, it is not unique and not sufficient.
For 2), A mode 6=0,2, it is not unique and not sufficient.
When 1) & 2), only A mode 6=2 is derived, which is unique and sufficient.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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04 May 2016, 07:08
As always, there are some advanced questions that are combined with the Common Mistake Type #3 and #4. Let’s have a look at the example below. This is a very recent type of questions, which also belongs to the mistake type 4(A). Since such types of questions appear in the level of score 50-51, you should be able to get them right for high scores. To this end, you should be aware of the relationship between the Variable Approach Method and the Common Mistake Types.
If the average (arithmetic mean) height of John, Tom and Jack is 1.70m, what is the median height of them?

1) The height of Tom is 1.65m.
2) The height of Jack is 1.70m

The answer to the above question is C but also B at the same time. This is a typical question that appears in the level of score 50-51. For high scores, you should be able to tack these types of questions. Focus on integer or statistics questions, which can make C an answer!
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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08 May 2016, 18:27
Some of difficult questions are related to our daily lives. You need to get them right for the perfect 51.
A bank has a number of coins which equals \$3.35 in total. There are only 2 types of coins: \$0.25 each and \$0.1 each. What is the remainder when the number of \$0.1 coins is divided by 5?
I. 0 II. 1 III. 2
A. I only B. II only C. I & II only D. I & III only E. I, II & III

This type of questions seems simply, but they are rather quite challenging. We call this type of questions as hidden integer questions.
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10 May 2016, 18:42
As always, the more advanced questions combined with the Common Mistake Type 3 and 4 frequently appear in the GMAT Math. Let's have a look at the question below. It is one of the most current type of the question. This question can also be described as the question involving Common Mistake Type 4(B), which appears in the level of score 50-51. You have to be very confident with questions like this. You have to know the relationship between Variable Approach Method and the mistake types.

The probability that event A occurs is 0.4 and the probability that event B occurs is 0.8. What is the probability that event A occurs but not event B?
1) Event A and event B are independent.
2) The probability that neither event A nor event B occurs is 0.32.

From the original condition, we only have to know P(A∩B). Hence, there is only 1 variable in the original condition, making D the mostly likely answer. Using the condition 1) and the condition 2), we can see the condition 1)=the condition 2). Hence, D is the correct answer.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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11 May 2016, 19:53
This is a question related to the Common Mistake Type 4(A). You should be extra cautious on such type of questions.
If x, y are positive integers, what is the remainder when 2^(4x+2)+y is divided by 5?
1) x=3
2) y=1
Remainder questions that require you to divide the question by 5 has a cycle of 5. In other words, we get (~2)^1=~2, (~2)^2=~4, (~2)^3=~8, (~2)^4=~6.
Hence, the cycle of 4 is 24862486.
If we modify the original condition and the question, when we are dividing 2^(4x+2)+y by 5, we do not have to consider 4x. So, we need to consider only about 2^(2)+y. Since we only have to know y, the correct answer is B.

This is a type of questions that appears in the score range of 50-51.
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Re: The Ultimate Q51 Guide [Expert Level]  [#permalink]

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15 May 2016, 20:37
As always, the more advanced questions combined with the mistake type 3 and 4 are frequently given on GMAT Math. Let's have a look at the question below, which is a current question. This question is also the mistake type 4(A), which is on the level of score 50-51. You have to be very confident with questions like this. You have to know the relation between approach method to variables and the mistake types. In particular, questions including number and ratio are frequently given, in which ratio is always an answer. The question below also contains 1) ratio and 2) number and the answer is A as well.

(ex 1) When x and y are integers, is x+y an even?
1) 3x+5y=even.
2) (x+1)2(y+1)2=even.

In the original condition, there are 2 variables. Hence, even though C could be the answer, considering the relationship between the Variable Approach Method and the Common Mistake Type, we can see that the condition 1) is always yes because x=y=even or x=y=odd. The condition is sufficient and the answer is A.

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16 May 2016, 19:39
There is an increasing number of geometry questions. For example:
A quadrilateral is inscribed in a circle as above figure. What is the measurement of ∠R?
1) The radius of the circle is 5
2) The line segment PS is equal to the diameter of the circle.
The central angle is twice the angle of circumference. PRS=90 degrees. Hence, the correct answer is B.
Attachments

.png [ 10.36 KiB | Viewed 2823 times ]

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18 May 2016, 15:35
(ex 2) A, B are two sets whose elements are integers, A∪B represent union set of two sets A, B. Is each of the elements in the set A divisible by 3?
1) A∪B={13,17,31,47,52}
2) B={13,17,47}

Also, questions involving the Common Mistake Type 4(A) is very tricky.
(ex 2) A, B are two sets whose elements are integers, A∪B represent union set of two sets A, B. Is each of the elements in the set A divisible by 3?
1) A∪B={13,17,31,47,52}
2) B={13,17,47}

There are questions that involve both the common mistake type 1 (no is also an answer) and the common mistake type 4(A). In above question, C is also an answer. If we look at that condition 1), even if A’s elements are any numbers, it cannot be divided by 3. The answer is no and the condition is sufficient. Therefore, the correct answer is A.
This is a type of questions that appears in 50-51.
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Re: The Ultimate Q51 Guide [Expert Level]   [#permalink] 18 May 2016, 15:35

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# The Ultimate Q51 Guide [Expert Level]

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