<p>This is from section 8, OC Test 6. I left 3 blank (ran out of time ><), but got the rest right. There’s only one question I’m not sure how to do. I figured out the others, but want to know if there’s a shorter way.</p>
<h1>11</h1>
<p>Probability kills me I know for sure it’s not A, but I don’t know how to continue.</p>
<h1>15</h1>
<p>I got this right when I did it after I corrected the section. I put both equations in slope intercept form and just calculated what value of k would make the slopes equal and thus made the lines parallel (which means no solution). Is there a faster way?</p>
<h1>16</h1>
<p>Again like 15, figured this one out but want to see if there’s a faster way. III is immediately obvious as true, so that eliminates A and B. A quick glance also finds that I is true, eliminating D. We’re left with C and E. To evaluate II, I set up two columns, hit and miss. I went down the table - 7 people missed on first throw, add 7 to miss column. 6 people hit on the first but 6 missed on the second, add 6 to both columns and so on. This method yields the right answer E, but is there a faster way?</p>
<p>I won’t post the actual question, but to give you an idea of #11, it’s one of those problems where you have x number of blue marbles, x number of black etc. all in a jar. It then asks what is the least number of marbles that must be picked to ensure that you’ve picked y or more ____ colored marbles.</p>
<p>James i got numer 11 ,it has almost nothing to do with probability.Listen
If you select 6 boxes and if you are unlucky you can get 2 red,2blue,2 yellow and 0 gray boxes.You cannot be sure that you will get 3 boxes with the same color
Same story if you select 7 boxes -they could be 2 red-2 blue-2yellow-1gray (again no 3 boxes with the same color.
If you select 8 boxes - 2-2-2-2
But if you select 9 boxes you could be absolutely ,100% sure that at least 3 of the boxes with be with the same color.Answer E
I will check the other questions as soon as possible ;] I am going to watch the Man United game now :p</p>
<ol>
<li>the “number” shows when the person missed it.
I. 17 missed the first one, 18 went beyond. its true
II. total throws = 7+12+18+16+10=63
missed targets=25; 63-25=38; which makes it true
III. you don’t see a “6” so its true :P</li>
</ol>
<p>@ Boyan: it’s OK, looks like timmy and I both used the same principle to solve the problem. If two lines have the same slope but a different y intercept, they do not intersect.</p>
<p>^ Calculating what value of k makes the determinant 0, rendering the system of equations solution-less. It’s pretty cool how there are so many different ways of solving even simple problems :)</p>
I know for sure it’s not A, but I don’t know how to continue.</p>