Question 1075570
 Roll two dice once. Let A be the event that the sum 
of the two dice is 10... 
a) P(A)=
<pre>
Here are all 36 possible dice rolls with the
ones with sum 10 colored red:

(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)

(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)

(3,1) (3,2) (3,3) (3,4) (3,5) (3,6) 

(4,1) (4,2) (4,3) (4,4) (4,5) <font color="red"><b>(4,6)</b></font> 

(5,1) (5,2) (5,3) (5,4) <font color="red"><b>(5,5)</b></font> (5,6)

(6,1) (6,2) (6,3) <font color="red"><b>(6,4)</b></font> (6,5) (6,6)

Count the red ones, there are 3.  

So P(A) is 3 out of 36 = 3/36 = 1/12
</pre>
...and B be the event that at least 
one of the dice is odd.
b) P(B)=  
<pre>
Here are all 36 possible dice rolls with the 
ones that have at least one of the dice odd in red:

<font color="red"><b>(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)</b></font>

<font color="red"><b>(2,1)</b></font> (2,2) <font color="red"><b>(2,3)</b></font> (2,4) <font color="red"><b>(2,5)</b></font> (2,6)

<font color="red"><b>(3,1) (3,2) (3,3) (3,4) (3,5) (3,6)</b></font> 

<font color="red"><b>(4,1)</b></font> (4,2) <font color="red"><b>(4,3)</b></font> (4,4) <font color="red"><b>(4,5)</b></font> (4,6) 

<font color="red"><b>(5,1) (5,2) (5,3) (5,4) (5,5) (5,6)</b></font>

<font color="red"><b>(6,1)</b></font> (6,2) <font color="red"><b>(6,3)</b></font> (6,4) <font color="red"><b>(6,5)</b></font> (6,6)

Count the red ones, there are 27.  

So P(B) is 27 out of 36 = 27/36 = 3/4
</pre>
c) Find the probability that the sum of the two dice is at least 9.
<pre>

Here are all 36 possible dice rolls with the
ones with sum of the dice at least 9 colored red:

(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)

(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)

(3,1) (3,2) (3,3) (3,4) (3,5) <font color="red"><b>(3,6)</b></font> 

(4,1) (4,2) (4,3) (4,4) <font color="red"><b>(4,5) (4,6)</b></font> 

(5,1) (5,2) (5,3) <font color="red"><b>(5,4) (5,5) (5,6)</b></font>

(6,1) (6,2) <font color="red"><b>(6,3) (6,4) (6,5) (6,6)</b></font>

Count the red ones, there are 10.  

So P(sum&#8805;9) is 10 out of 36 = 10/36 = 5/18.

Edwin</pre>