lucalelli88 wrote:

I HAVE SOME DOUBT IN SOME QUESTION I HOPE THAT SOMEONE CAN HELP ME HERE IN GMATCLUB..

1.

fritz is taking an examination that consist of two parts A and B with the following instructions:

Part A must be completed before starting part B

Part A contains 3 questions and a student must answer two

Part B contains 4 questions and a student must answer two.

in how many ways can the test be completed

A 12

B 15

C 36

D 72

E 90

This question doesn't really make sense.

Assuming that order doesn't matter when answering questions within Part A or Part B:

3C2 * 4C2 = 3 * 6 = 18.

Assuming order does matter when answering questions within each part. I'm not sure why this would occur given the information in the problem statement.

3P2 * 4P2 = 6 * 12 = 36.

lucalelli88 wrote:

2.

the university of Maryland, university of Vermont and Emory University have each 4 soccer players. if a team of 9 is to be formed with an equal number of players from each university, how many numbers of ways can the selections be done?

A 3

B 4

C 12

D 16

E 25

"the university of Maryland, university of Vermont and Emory University have each 4 soccer players."

3 bags of 4: M1,M2,M3,M4 V1,V2,V3,V4 E1,E2,E3,E4

"if a team of 9 is to be formed"

combo box arrangement

(_)(_)(_)(_)(_)(_)(_)(_)(_)/9! <--------the next clause indicates that this is not the correct setup for the problem.

"with an equal number of players from each university"

Oops. Rewrite the combo box arrangement.

divide the combo box arrangement into 3 groups

(_)(_)(_)/3! Maryland

(_)(_)(_)/3! Vermont

(_)(_)(_)/3! Emory

"how many numbers of ways can the selections be done?"

Fill in the boxes.

(4)(3)(2)/3! * (4)(3)(2)/3! * (4)(3)(2)/3! = 4*4*4 = 64

lucalelli88 wrote:

3

Each employee at a certain bank is either a clerk or an agent or both. of every 3 agents one is also a clerk. of every two clerks, one is also an agent. what is the probability that an employee randomly selected from a bank is boh an agent and a clerk?

A 1/2

B 1/3

C 1/4

D 1/5

E 2/5

"Each employee at a certain bank is either a clerk or an agent or both. "

C,A,CA

"of every 3 agents one is also a clerk."

1: A

2: A

3: AC

"of every two clerks, one is also an agent."

1: A

2: A

3: AC

4: C

Total = 4

"what is the probability that an employee randomly selected from a bank is boh an agent and a clerk?"

Employee #3 / Total = 1/4

lucalelli88 wrote:

and i want to add just a question.

when i face with a probability problems like in a box there 32 blu marbles and 12 red marbles... which is the probability that picking two marbles are both red? in these case when someone picks at the same time more than one marbles what do i have to do to solve it? thanks

Probability Table: Create and work backward.

# of reds

0:

1:

2:

------------------------------

Total =

******************************************

Total = Bag of 44, pick 2 = 44C2 = 44*43/2 = 22*43 = 946

2 reds: 12 reds, pick 2 = 12C2 = 12*11/2 = 6*11 = 66

1 red: 12 reds, pick 2 * 32 blues = 12C1 * 32 = 12 * 32 = 384

0 reds: Total up the column = 946 - 66 - 384 = 496.

Or, 32 blues, pick 2 = 32C2 = 32*31/2 = 16*36 = 496.

******************************************

# of reds

0: 496

1: 384

2: 66

------------------------------

Total = 946

******************************************

Use the table to answer any probability question.

P(red = 0) = 496/946

P(red = 1) = 384/946

P(red = 2) = 66/946

P(no reds or all reds) = (496+66)/946

P(less than 2 reds) = (384+496)/946