Search found 10 matches
A bag contains 3 red, 4 black and 2 white balls. What is the probability of drawing a red and a white ball in two successive draws, each ball being put back after it is drawn? (A) 2/27 (B) 1/9 (C) 1/3 (D) 4/27 (E) 2/9 3R, 4B, 2W balls. Total = 9 balls prob(RW) = Prob(R)*Prob(W) (independent events ...
- by naveen1003
Thu Jun 09, 2011 3:08 am- Forum: Problem Solving
- Topic: Difficult Math Question #9
- Replies: 5
- Views: 4888
A certain quantity of 40% solution is replaced with 25% solution such that the new concentration is 35%. What is the fraction of the solution that was replaced? (A) 1/4 (B) 1/3 (C) 1/2 (D) 2/3 Let total solution is 100 and x is replaced. Thus we have 40% of (100-x) solution and 25% of x solution = ...
- by naveen1003
Thu Jun 09, 2011 3:03 am- Forum: Problem Solving
- Topic: Difficult Math Question #7
- Replies: 5
- Views: 5365
A and B ran a race of 480 m. In the first heat, A gives B a head start of 48 m and beats him by 1/10th of a minute. In the second heat, A gives B a head start of 144 m and is beaten by 1/30th of a minute. What is B's speed in m/s? (A) 12 (B) 14 (C) 16 (D) 18 (E) 20 distance = 480m = d B is given he...
- by naveen1003
Thu Jun 09, 2011 3:00 am- Forum: Problem Solving
- Topic: Difficult Math Question #6
- Replies: 9
- Views: 21126
Question - Guard Patrol: The organizers of a week-long fair have hired exactly five security guards to patrol the fairgrounds at night for the duration of the event. Exactly two guards are assigned to patrol the grounds every night, with no guard assigned consecutive nights. If the fair begins on a...
- by naveen1003
Thu Jun 09, 2011 2:50 am- Forum: Problem Solving
- Topic: Manhattan GMAT 700+ problem - August 28, 2006
- Replies: 4
- Views: 4466
A certain ball was dropped from a window 8 meters above a sidewalk. On each bounce it rose straight up exactly one-half the distance of the previous fall. After the third bounce the ball was caught when it reached a height of exactly 1 meter above the sidewalk. How many meters did the ball travel i...
- by naveen1003
Thu Jun 09, 2011 2:42 am- Forum: Problem Solving
- Topic: help with this
- Replies: 12
- Views: 6576
If a 3-digit integer is selected at random from the integers 100 through 199, inclusive, what is the probability that the first digit and the last digit of the integer are each equal to one more than the middle digit? let abc be the required 3 digit number. condition: a=c=b+1 thus once we select b,...
- by naveen1003
Thu Jun 09, 2011 2:36 am- Forum: Problem Solving
- Topic: help with this
- Replies: 12
- Views: 6576
In a basketball contest, players must make 10 free throws. Assuming a player has 90% chance of making each of his shots, how likely is it that he will make all of his first 10 shots? Chance of making a shot = 90% Probability of making a shot = 0.9 Thus probability of making all of first 10 shots = ...
- by naveen1003
Thu Jun 09, 2011 2:25 am- Forum: Problem Solving
- Topic: Difficult Math Question #4
- Replies: 5
- Views: 3458
M=Z+4+ X Y Z
4 1 -5 M
E 7 N 10
F 2 -4 5
In the addition table shown above, what is the value of M + N =?
A. -19
B. 4
C. 5
D. 6
E. 22
N=Y+E
M+N = Z+Y+E+4 -equation 1
X+4 = 1; X=-3
Y+4=-5; Y=-9
X+E=7; E=10
Z+E=10; Z=0
thus M+N = 0+(-9)+10+4 = 5
IMO C
- by naveen1003
Thu Jun 09, 2011 2:19 am- Forum: Problem Solving
- Topic: Addition Table
- Replies: 13
- Views: 14291
The residents of Town X participated in a survey to determine the number of hours per week each resident spent watching television. The distribution of the results of the survey had a mean of 21 hours and a standard deviation of 6 hours. The number of hours that Pat, a resident of town X, watched t...
- by naveen1003
Thu Jun 09, 2011 1:11 am- Forum: Problem Solving
- Topic: Standard Deviation
- Replies: 3
- Views: 4020
- by naveen1003
Thu Jun 09, 2011 1:03 am- Forum: Problem Solving
- Topic: Quadratic Equation
- Replies: 5
- Views: 4113