Explanation for answer

[keerthivivek]

PART I
I don't know the reason why I got the following questions wrong in my power prep test 1. Can someone explain me the solution with explanation ? pls see the attachment for questions.

PART II
I am preparing for the past 3 months for GMAT exam. My target score is 720. I got 640 in my first power prep test( VERBAL = 33 / QUANS = 44). Many SCs errored out towards the end of VERBAL section. I guess I need to improve on RCs as well.

In quans, many PS questions errored out towards the end of the section.

My MGMAT test score is in the ballpark of 630, while my Kaplan is a meagre 560.

My GMAT exam is scheduled on May 22. What next steps do you suggest ? I am not sure on how to analyze my mistakes. Can any of the forum members share the depth to which we should identify flaws to fix them? for example, if careless in problem solving due to fast calculation, what is the fix ? More practice with few extra seconds of devotion to the calculation ?

Thanks in advance for reading this lengthy post. Pls let me know whether I should provide more inputs in order for you to understand my request.

[mba.dude]

Here is the solution to your questions. Hope I am clear. Let me know if you don't uderstand the explanation.

1st Ques:
Let us assume the salary of Mary, Jim and Kate as M , J and K.

As per the question:

M-J = 2(M-K)

M-J = 2M-2K

2K-J = M

The average of salaries of Mary, Jim and Kate will be :

J + K + M / 3

J + K + 2K-J / 3

3K/3 = K

So, The average of 3 salaries is kate's salary.

Statement 2 Alone is sufficient.



2nd Ques :
What is a median ?
The middle value in a set of numbers arranged in increasing order. If there is an even number of values, then median is the average of the middle two values

So, if you arrange all the number of amounts in ascending order, you will get the median by the average of middle two values.

48,48,70,70,70,80,80,80,80,84,84,84,84,84,84,84,96,96,96,96

The middle two values are 84, so the median is 84.

3rd Ques :
Let x be the amount by which the height increases every year.

So the ht after 6 yrs = 4+6x.
Ht after 4 yrs = 4+4x.

AS per the statement, At the end of 6th year, the tree was 1/5 taller thanit was at the end of 4th year.

4+6x = 4+4x + 1/5(4+4x)

2x = 4/5 + 4/5x

(2-4/5)x = 4/5

6/5x = 4/5

x = 4/6 = 2/3.

[keerthivivek]

Thanks mba.dude for your help on the explanation.

[rey.fernandez]

Another way to go about the problem is to ask why did they say that Mary's salary is the highest? Information like that must be useful in some way...

Well, what that means is that Jim's salary is the lowest among the three, and therefore Kate's is in the middle -- in fact Kate's salary is exactly in the middle between Jim's and Mary's. We know this because the difference between Jim's and Mary's is twice the difference between Kate's and Mary's.

So that means that Kate's salary equals the average of the three salaries. (2) is therefore sufficient while (1) is not.