<p>oh good, i gridded in 1.5, but i couldn't remember the actual question.
thanks !</p>
<p>could someone explain the 3 digit problem more extensively...i am too dumb to understand the short concise explanation by prospective</p>
<p>Another answer to the sq root x plus sq root y = 10 problem is 50 when x and y both equal 25.... the problem never said that x and y couldn't be equal!!</p>
<p>^hm good point except I have yet to see such an ambiguous math question from the CB, so I suppose we can assume when they specify an X and a Y, they are distinct terms, or else CB would just say sq root x plus sq root x</p>
<p>They don't require distinct unless they specify for distinct. They did, however, require that both numbers be odd.</p>
<p>sorry akati, I'll try to explain in more depth:</p>
<p>The problem required you to find the number of three digit integers that meet the following requisites:</p>
<p>1) the digit in the one's place must be a 2
2) the other digits can be 3,4,5,6,7
3) no two of the same digit can be juxtaposed</p>
<p>If you've taken Pre-Calc (or perhaps Alg II), this problem is easy. You have three slots for each digit in the integer. Each slot represents the number of possibilities for the digit corresponding to that slot. The final number of possibilities (and the answer to the problem) is the product of all three. You can set up the slots as follows using 1 in the one's place since you know it must be 2. Observe (the 'x' is the product sign): </p>
<p>_ x _ x 1</p>
<p>There are now two empty slots. The first one can be one of any of the following 3, 4, 5, 6, 7. So the value for that slot is a 5:</p>
<p>5 x _ x 1 or _ x 5 x 1 (they're the same)</p>
<p>Finally, the last digit can be any of the ones mentioned above, however, it can not be the same. This limits it to four possible choices (all choices except the one occupying the first slot so 5-1=4). Therefore, the number of possibilities is:</p>
<p>5 x 4 x 1=20</p>
<p>Or you can use the time-consuming method the CB wants to lure you into by listing all the possibilities...</p>
<p>bump
pmub
bump
pmub</p>
<p>you'llsee... said:</p>
<p>Okay.....Let me end this dispute right now. My explanation is 100% right....</p>
<p>Q: sqrt X + sqrt Y = 10</p>
<p>If X and Y are odd intergers, what is the sum of X + Y</p>
<p>X and Y both had to be ood (49 and 9) or (81 and 1)..........their sum DID NOT have to be odd....X AND Y HAD TO BE ODD....NOT THEIR SUM....I REPEAT....X AND Y ADD TO BE ODD INTERGERS NOT THEIR SUM........</p>
<p>sorry to use so many caps, but i had to clarify this for all of you. Again, I am 100% sure my explanation is correct.</p>
<p>okay, now let's move on.....</p>
<hr>
<p>Just one thing to add to that - another possible answer is if X and Y are both 25, meaning that their root is 5, and their roots add to make 10. As you said, their sum doesn't have to be odd, so it works.</p>