Search found 4 matches
picking marbles from a bag - combination explanation plz
From a bag containing 4 white and 5 black balls a man draws three at random what is the probability of these being all black.
5C3 / 9C3
can someone explain the answer and how we use the combination formula
- by wahooza
Thu Nov 18, 2010 8:40 pm- Forum: GMAT Math
- Topic: picking marbles from a bag - combination explanation plz
- Replies: 1
- Views: 4024
well...those are the most accurate indicators of the GMAT u can get. its about + or - 20 points of the GMAT prep... i recognized passages/questions straight up from OG. in fact, one of the reading comp, i didnt even have to read (although i did) because i remembered it from the OG. i dont imagine t...
- by wahooza
Tue Nov 16, 2010 1:08 pm- Forum: GMAT Strategy
- Topic: GMAT prep test accuracy
- Replies: 2
- Views: 2311
Is x a negative number? (1) x2 is a positive number. (2) x × |y| is not a positive number. OA - E rephrase: x<0? (1) x^2 = positive. square of negative = positive. square of positive = positive so x can either be positive or negative. Insufficient (2) x * |y| <= 0 (warning as i'm reading: not a po...
- by wahooza
Thu Nov 11, 2010 11:43 am- Forum: Data Sufficiency
- Topic: 700+
- Replies: 4
- Views: 1190
rephrasing tactic - general
if my data sufficiency question is "what is 6x+60" can i rephrase it to "what is x" vs. another question is "what is x-y" rephrasing to to "x=? and y=?" would be restricting my answers for the 2nd question, i can find x-y without finding x and y.... right? is ...
- by wahooza
Thu Nov 11, 2010 11:20 am- Forum: Data Sufficiency
- Topic: rephrasing tactic - general
- Replies: 1
- Views: 987