gowani wrote:
A store buys 10 bottles of alcohol,
Bag of 10 choices.
gowani wrote:
including 7 bottles of whiskeys.
Bag is made of 7 whiskey and 3 nonwhiskey.
gowani wrote:
In the evening, 6 bottles of alcohol are sold one by one
Combo box arrangement
(_)(_)(_)(_)(_)(_)/6!
gowani wrote:
and the rest is consumed by the personnel.
um...ok. drinkdrinkdrinkdrinkdrink
gowani wrote:
What is the probability of selling 4 whiskeys among the 6 bottles?
Probability Table: Create and work backwards.
# of Whiskey: Events
0:
1:
2:
3:
4:
5:
6:
-------------------------------------
Total =
*******************************************************
Total = 10 bottles pick 6 = 10C6 = 10*9*8*7*6*5/6*5*4*3*2*1 = 210
6 Whiskey: 7 whiskey pick 6 = 7C6 = 7 <---------don't need this, but good for practice.
5 Whiskey: 7 whiskey pick 5 AND 3 non whiskey pick 1 = 7C5 * 3C1 = 63 <----------don't need this either.
4 Whiskey: 7 whiskey pick 4 AND 3 non pick 2 = 7C3 * 3C2 = 105 <-----This is what we need. I'll finish the table for fun.
3 Whiskey: 7 whiskey pick 3 AND 3 non pick 3 = 7C3 * 3C3 = 35
OR sum the table total: 210 - (7+63+105) = 35
2 Whiskey: 7 whiskey pick 2 AND 3 non pick 4 = impossible = 0
1 Whiskey: also impossible = 0
0 Whiskey: also impossible = 0
*******************************************************
# of Whiskey: Events
0: 0
1: 0
2: 0
3: 35
4: 105
5: 63
6: 7
-------------------------------------
Total = 210
*******************************************************
Use the info in the table to answer any probability question.
P(Whiskey = 4) = 105/210 = 1/2
P(Whiskey = prime number) = (0+35+63)/210
P(Whiskey > 3) = (105+63+7)/210
gowani wrote:
Assume that every bottle has an equal chance of being bought.
A. 2/5
B. 3/5
C. 2/3
D. 1/2
E. 4/7
ANS: D