Search found 24 matches


Take the task of creating suitable 3-digit numbers and break it into stages. Stage 1: Select the single digit that will be different from the other 2 digits We can choose any of the following 9 digits: 1, 2, 3, 4, 5, 6, 7, 8 or 9 So, we can complete stage 1 in 9 ways Stage 2: Choose where that sing...

by Zoser

Mon Dec 04, 2017 7:58 am
Forum: Problem Solving
Topic: permutation gmat
Replies: 10
Views: 3956

Take the task of creating suitable 3-digit numbers and break it into stages. Stage 1: Select the single digit that will be different from the other 2 digits We can choose any of the following 9 digits: 1, 2, 3, 4, 5, 6, 7, 8 or 9 So, we can complete stage 1 in 9 ways Stage 2: Choose where that sing...

by Zoser

Mon Dec 04, 2017 5:57 am
Forum: Problem Solving
Topic: permutation gmat
Replies: 10
Views: 3956

The first sock selected can be any color.
Of the 5 remaining socks, 3 will be selected.
Isn't the second selection to match the first color is 1/5 not 3/5?

by Zoser

Sat May 27, 2017 10:11 am
Forum: Problem Solving
Topic: Probability - 2 Pairs of Socks
Replies: 14
Views: 23164

WHat is wrong with this approach?

P(6 at least)= 1-P(not at least 6)

= 1-P(1 and 2 and 3 and 4 and 5 correct answers)

we have 5 correct answers with P= 1/2*1/2*1/2*1/2*1/2= 1/2^5 = 1/32

1-1/32 = 31/32

Why is my approach wrong?

by Zoser

Thu May 25, 2017 5:15 am
Forum: Problem Solving
Topic: An exam consists of 8 true/ false questions
Replies: 8
Views: 3729

This approach allows for identical rectangles to be counted more than once. For example, in your approach, we might select (4,3) for point A, then select (10,3) for point B, then (4,-5) for point C and then (10, -5) for point D This gets counted as 1 outcome. However, if we select (10, -5) for poin...

by Zoser

Wed May 10, 2017 5:26 am
Forum: Problem Solving
Topic: wonderful P & C ques :
Replies: 15
Views: 9016

I solved it this way: Rectangle ABCD Stage 1: Choosing point A. The grid for this point is 9*11= 99 Stage 2: Choosing Point B. As Point B lies on the same y coordinate, we have 1 value for y and 8 possible values for x as one value of x is already taken for point A. Point B can be chosen in 8*1= 8 S...

by Zoser

Wed May 10, 2017 5:05 am
Forum: Problem Solving
Topic: wonderful P & C ques :
Replies: 15
Views: 9016

What would the answer be if the question said 3 AND 6 instead of 3 or 6?

by Zoser

Mon May 01, 2017 4:20 am
Forum: Problem Solving
Topic: Digits, Numbers
Replies: 6
Views: 5343

Statement 2: 11! - 12 < y < 11! - 2
Let's examine a few possible values for y.

y = 11! - 11
Why you started with 11!-11 not 11!-12?

by Zoser

Sat Apr 15, 2017 6:13 am
Forum: Data Sufficiency
Topic: is y prime?
Replies: 4
Views: 3731

Sorry, that should have read "Among a set of consecutive integers, every 3rd integer will be divisible by 3" This statement is true. For example: 4, 5, 6, 7, 8, 9, 10, 11, 12, 13... What about: 2,3,4,5,6,7,8,9 4 and 7 are not divisible by "3" eventhough 4 is the 3rd consecutive ...

by Zoser

Wed Apr 12, 2017 4:17 am
Forum: Data Sufficiency
Topic: how to solve fast: divisibility
Replies: 6
Views: 3530

Statement 1: N is divisible by 3 IMPORTANT RULE: Among a set of integers, every 3rd integer will be divisible by 3. Likewise, every 4th integer will be divisible by 4. Every 5th integer will be divisible by 5. Does this rule work all the times? I tried number 9223 and it is not divisible by 3! Thanks

by Zoser

Wed Apr 12, 2017 3:20 am
Forum: Data Sufficiency
Topic: how to solve fast: divisibility
Replies: 6
Views: 3530

The three angles along the x-axis must sum to 180. In Brent's solution, the leftmost angle along the x-axis = 30. The figure indicates that the middle angle along the x-axis = 90. Thus, the rightmost angle along the x-axis = 180-30-90 = 60. Result: The triangle on the right is also a 30-60-90 trian...

by Zoser

Thu Mar 09, 2017 10:12 am
Forum: Problem Solving
Topic: Co-ordinate geometry
Replies: 10
Views: 5919

This is possible only if the LENGTH of the original sheet is reduced by half, while the original width STAY THE SAME.
Can you elaborate more on this statement? For example, w=8, L=14 so 8/14 to 8/7, why we flip 8/7 to 7/8?
it should be

Original W/original L compared with New W/new L?

by Zoser

Thu Mar 09, 2017 10:09 am
Forum: Problem Solving
Topic: PS - rectangles
Replies: 4
Views: 4079

Here's one approach:
H Brent,

Can you explain why you assumed in your solution that the second triangle is 30:60:90? like the traingle on the left?

I know the r=2 but this does not mean that the second triangle is the same as the triangle to the left.

Wham am I missing here?

by Zoser

Thu Mar 09, 2017 9:41 am
Forum: Problem Solving
Topic: Co-ordinate geometry
Replies: 10
Views: 5919

Equilateral triangles and 30-60-90 triangles are common bedfellows. Equilateral triangles and 45-45-90 triangles are not. There is almost no chance that the perimeter of an equilateral triangle on the GMAT will involve √2, which is associated with a 45-45-90 triangle. Hi. I dont understand why it...

by Zoser

Tue Mar 07, 2017 5:25 pm
Forum: Problem Solving
Topic: PS - Triangle
Replies: 14
Views: 6078

You bet!
Great Approach!

I also did the below and it gave me a correct answer:

I equaled Car X distance with Car Y distance by adding 1 to Y`s distance

(50/60)*m = {(40/60)*m}+1..... where m is number of minutes

5m/6 = (2m+3)/3
15m = 12m+18
3m = 18
m = 6

What do you think?

by Zoser

Wed Feb 22, 2017 9:03 am
Forum: Data Sufficiency
Topic: Cars X and Y speeds
Replies: 6
Views: 3967