<p>I hope this isn't considered spamming; I thought it'd just be easier to separate my questions by subject/section.</p>
<p>1) How many different ordered pairs (x,y) are there such that x is an even integer, where 4 < x < 10, and y is an integer, where 4 < y < 10?</p>
<p>Answer is 20.</p>
<p>2) If j is chosen at random from the set {4,5,6} and k is chosen at random from the set {10,11,12}, what is the probability that the product of j and k is divisible by 5?</p>
<p>Answer is 5/9.</p>
<p>As you can see, I tend to have issues with probability questions. -__-</p>
<p>For the first one, I would just write it out. (Though there’s probably a faster way to solve it)
For the 2nd one, find the number of all possible products of j and k, which happens to be 9. (3 x 3) then you would want to find the number of all possible products of j and k that are divisible by 5 (out of the 9 possible products of j and k) and that happens to be 5. So therefore 5/9, or 5 out of the 9 possible products of j and k are divisible by 5.</p>
<p>For 1) x can be 4,6,8,10 and y can be 6,8. I only got 8 pairs, not 20 though… am I just stupid?</p>
<p>y is any integer not and even one. So 5,6,7,8,9 would all work.</p>
<p>You need to read the directions very carefully.</p>
<p>1)</p>
<p>X can be 4 things (4,6,8,10)
Y can be 5 things (5,6,7,8,9)</p>
<p>(X,Y) can be 4*5 = 20</p>
<p>2.)</p>
<p>P = Win/Possible Outcomes</p>
<p>Possible Outcomes = 3*3 = 9
Wins = 3 + 3 - 1 = 5</p>
<p>5/9</p>
<p>The “-1” was because of overcount.</p>
<p>Of course not =) Just have to read carefully. The problem says “y is an integer, where 4<y<10” so y is not limited to just 6,8. X can be 4,6,8,10 and y can be 5,6,7,8,9; therefore to find all the possible pairs, you would multiply 4 by 5 and you get 20.</p>