Search found 23 matches
Increasing a quantity by 100% is the same as multiplying that quantity by 2 (adding the whole amount on top of what's already there). So we can say that every 5 months the established organization doubles its membership. To see how we can then get an expression for the members of the organization af...
- by Danny@GMATAcademy
Sat Jan 28, 2017 8:14 am- Forum: Problem Solving
- Topic: Percentage Problem
- Replies: 2
- Views: 1643
Here are a couple of ways to think about this problem:
OG17 Q201 Method 1: https://www.youtube.com/watch?v=oFFH0y9H0ZU
OG17 Q201 Method 2: https://www.youtube.com/watch?v=LI168d14Ark
- by Danny@GMATAcademy
Fri Jan 27, 2017 8:52 am- Forum: Problem Solving
- Topic: OG-17 Problem solving
- Replies: 5
- Views: 2799
We can rewrite x as 4m, and y as 9n, where m and n are integers. The question is: Will 42 divide evenly into xy? Or... Will the denominator of xy/(42) cancel out completely? Or... Will the denominator of xy/(2*3*7) cancel out completely? Or... Will the denominator of (4m*9n)/(2*3*7) cancel out compl...
- by Danny@GMATAcademy
Wed Jan 11, 2017 11:33 am- Forum: Data Sufficiency
- Topic: If 4 is a factor of positive integer
- Replies: 5
- Views: 3018
We can use the "add up the rates to get the combined rate " method to build an equation. (rsarashi, I think this is what you are referring to -- in your example, 1/k is a rate; something can do 1 job in k hours, or 1/k jobs per hour) X's Rate + Y's rate = Combined rate Since Rate = (Work) ...
- by Danny@GMATAcademy
Wed Jan 11, 2017 9:47 am- Forum: Problem Solving
- Topic: One last help with proportions please
- Replies: 8
- Views: 3195
A couple of ways to solve this question:
Logic/Time-Formula approach:
https://www.youtube.com/watch?v=8OGY5xcYqDM
Rates/Algebra approach:
https://www.youtube.com/watch?v=B2PAbu157fw
- by Danny@GMATAcademy
Wed Jan 11, 2017 8:07 am- Forum: Data Sufficiency
- Topic: Three machines, K, M, and P, working simultaneously
- Replies: 7
- Views: 6798
Absolute value can be thought of as 'distance from zero.' Statement number 2 is saying that y is less than 10 away from zero. This means that if we were to draw the possible values of y on the number line, we'd get a closed segment (it wouldn't continue forever in either direction). A closed segment...
- by Danny@GMATAcademy
Tue Jan 10, 2017 8:53 am- Forum: Data Sufficiency
- Topic: y is an integer. What is the smallest possible value of y?
- Replies: 5
- Views: 3392
We can use the 'identical machines doing the same job' formula: (old # of machines)(old time) = (new # of machines)(new time) Plugging in, we get: (12)(8) = (new #)(6) (2)(8) = new # 16 = new # So we need sixteen machines to do the job in 6 days. In other words we need 4 additional machines. You can...
- by Danny@GMATAcademy
Sun Jan 08, 2017 10:04 pm- Forum: Problem Solving
- Topic: Doubt on Rate Problem
- Replies: 7
- Views: 3467
Here are a couple of ways to solve this problem:
Method 1 (add the rates): https://www.youtube.com/watch?v=zqeIIbSdEc4
Method 2 (Time Formula): https://www.youtube.com/watch?v=1LeaTvlAA-U
- by Danny@GMATAcademy
Sat Jan 07, 2017 1:14 pm- Forum: Problem Solving
- Topic: Pumping alone at their
- Replies: 5
- Views: 4955
The calculation error would be harder to make if you worked from simplest item to most complex:
Ways to deal with Z: 6
Ways to deal with Ys (assuming Z already placed): 5C2 = 10
Ways to deal with Xs (assuming Z and Ys already placed): 1
So 6*10*1 = 60
- by Danny@GMATAcademy
Thu Jul 21, 2016 7:14 am- Forum: Problem Solving
- Topic: Permutation and combination
- Replies: 6
- Views: 2932
Here's a video explanation for this question: https://www.youtube.com/watch?v=5iFLsVP2MO0 For more on the method used in the video above, see the videos below: Intro to the chart method for ratios: https://www.youtube.com/watch?v=WfHm5SF95vU Using the ratio chart in Data Sufficiency: https://www.you...
- by Danny@GMATAcademy
Wed Jul 13, 2016 10:32 am- Forum: Data Sufficiency
- Topic: OG 2017 Ratio Question
- Replies: 6
- Views: 3608
Most probability question that include the phrase 'at least' are easier to solve "backwards." that is, for such questions, it tends to be easier to find the probability of NOT getting what we want and then subtracting from one. (since, for example, if an event has a 3/4 prob of NOT occurri...
- by Danny@GMATAcademy
Mon Jul 11, 2016 8:19 am- Forum: Problem Solving
- Topic: Probability
- Replies: 2
- Views: 2747
(Number of liters in 2-liter bottle) + (Number of liters in 4-liter bottle) = 4 liters. if x = fraction of each bottle that ends up filled, the equation above can be rewritten: x(2) + x(4) = 4 x(2 + 4) = 4 x(6) = 4 x = 2/3 so each bottle is filled to 2/3 of its capacity. Therefore the 4L bottle has ...
- by Danny@GMATAcademy
Mon Jul 11, 2016 7:54 am- Forum: Problem Solving
- Topic: Mixture
- Replies: 4
- Views: 5153
Danny Sir, I am having a hard time understanding what the sentence seems to imply. The 1500 feetmentioned in the sentence implies which of the following. 1) The 5 hand brakes are spread over a distance of 1500 feet 2) OR With the help of these 5 hand brakes the train comes to a halt in 1500 feet. W...
- by Danny@GMATAcademy
Wed Jul 06, 2016 8:07 am- Forum: Sentence Correction
- Topic: SC - GMAT Prep
- Replies: 8
- Views: 4824
Value substitution and algebra both work nicely for this question. See videos below:
Value substitution: https://youtu.be/L-fqOMzmglM
Algebra: https://youtu.be/usxNJ89lAZs
Hope they help.
- by Danny@GMATAcademy
Tue Jul 05, 2016 5:22 pm- Forum: Problem Solving
- Topic: P/S need help...
- Replies: 5
- Views: 3999
A couple of ways to solve this problem:
Algebra:https://youtu.be/obHR1MewMhA
Balance Method:https://youtu.be/EkkOwiyrhhQ
- by Danny@GMATAcademy
Tue Jul 05, 2016 8:24 am- Forum: Problem Solving
- Topic: seed mixture
- Replies: 19
- Views: 14003