Please Help

rgeer

New member
Joined
Sep 14, 2005
Messages
32
Hello,

There are some problems that I need help on and that need verifying:

1)The probability that the Talbot Agency will win a new ad contract is 0.3. What is the probability that it will not win the contract.
Choose one: a)0.5 b)0.7 c)0.9 d)1.3

2)Two dice are rolled. What is the Probabilty that the sum is at least 2.
Choose One: a)0 b)1/6 c)3/4 d)1

3)Two dice are rolled. Find the prob. of each outcome:
a)At least one die shows a 5. I think its 1/12
b)Neither die shows a 2. I think its 0
c)the dice show different numbers. I think its 1
d)Exactly one die shows a 1. I think its 1/12

Thanks in advance,
Ryan
 

stapel

Super Moderator
Staff member
Joined
Feb 4, 2004
Messages
15,943
1) Hint: The probabilities of all the different events (in this case, two, being "yes" or "no") have to add up to "1" (for "100% of all the possibilities").

2) Make a six-by-six grid. Along the left-hand side, label from top to bottom from "1" to "6". Along the top, label from left to right from "1" to "6". Then fill each square in the grid with the sum of the numbers from the top of the grid and the side of the grid. For instance, the second square in the third row will have a "2" up top and a "3" to the left, so the sum would be "5".

Obviously, there are thirty-six possible outcomes. How many of those thirty-six are "2" or more?

3) Use a grid like that above.

a) Leave the grid's squares empty of numbers. Just shade in those squares that have a "5" for one or both of the labels. Count up the shaded squares, and divide by "36".

b) Leave the grid's squares empty of numbers. Just shade in those squares that aren't in the second row or second column. Count up the shaded squares, and divide by "36".

c) Leave the grid's squares empty of numbers. Note that, on the one diagonal, you have pairs with the same values for each die. Shade in the other squares.

d) Shade in only those squares on the first row and first column, except for one of the squares (that corresponds to both of the die having a "1" showing).

Eliz.
 
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