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: 3998
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: 3998
Isn't the second selection to match the first color is 1/5 not 3/5?The first sock selected can be any color.
Of the 5 remaining socks, 3 will be selected.
- by Zoser
Sat May 27, 2017 10:11 am- Forum: Problem Solving
- Topic: Probability - 2 Pairs of Socks
- Replies: 14
- Views: 23250
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: 3743
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: 9101
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: 9101
- by Zoser
Mon May 01, 2017 4:20 am- Forum: Problem Solving
- Topic: Digits, Numbers
- Replies: 6
- Views: 5374
Why you started with 11!-11 not 11!-12?Statement 2: 11! - 12 < y < 11! - 2
Let's examine a few possible values for y.
y = 11! - 11
- by Zoser
Sat Apr 15, 2017 6:13 am- Forum: Data Sufficiency
- Topic: is y prime?
- Replies: 4
- Views: 3744
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: 3555
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: 3555
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: 5972
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?This is possible only if the LENGTH of the original sheet is reduced by half, while the original width STAY THE SAME.
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: 4099
H Brent,Here's one approach:
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: 5972
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: 6092
Great Approach!You bet!
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: 3981