<p>Doesn't matter what/who he is. He's wrong.</p>
<p>did anyone answer 53 to some math q about the number of numbers in some range, divisible by some number?</p>
<p>yeppp</p>
<p>35-300
by 5x+1</p>
<p>I think the answer was 52. Just to make sure I have the method down pat:
1. 300-35 = 265
2 265/5 = 53
3. 53-1 = 52
** Because the numbers that X can equal are in this interval [7,60) or All real numbers from 7 (Inclusive) to 60 (Exclusive) meaning the answer is 52 possible values for X.</p>
<p>uhh, what was the question?</p>
<p>The question was, 5x+1= "some number between 35 and 300" it asked how many possible answers there were.</p>
<p>It is 53. I got it wrong too.</p>
<p>shucks.....</p>
<p>Oh, okay. I remember how I did it.</p>
<p>5x+1 = integers from 35 to 300
=> 5x = integers from 34 to 299
= integers under 299 - integers under 34
= floor(299/5) - floor(34/5)
= floor(59.8) - floor(6.8)
= 59 - 6
= 53</p>
<p>and i'm pretty sure you there are no shortcuts to make it any simpler than that, too. i don't think you can do straight out (a-b)/d nor floor(a-b)/d for the interval of [a,b] and a divisor of d like ach44 did, and always get the right answer, though it worked this time.</p>
<p>One way to do it is lattice points between 2 points is just the greatest common factor of the change in y over change in x. </p>
<p>Translating the graph down 1, we can have the values be 34 and 299. Then the difference is 265. 5x connects the points (7,35) and (60,300) We just have to find the points between these that are lattice points. That's just GCD of 60-7 and 300-35, which is 53. We don't subtract 1 even though it counts the endpoint because the starting point fits the criteria.</p>
<p>Wait... but shouldnt you be rounding 6.8 up to 7. Because 6 is not an actual value that X can be. You can't have a value that x can actually equal (59) and have the other number as an impossible value for X(6) I apologize for being so difficult, but I actually want to know how to do this problem, even if I am wrong.</p>
<p>arghhhh, lattice points!</p>
<p>i've been meaning to read up on them -
i just actually just bookmarked the wiki three days ago.</p>
<p>thanks bandito.</p>
<p>edit: ach44,
well by the time we get to that step, with floor(6.8), the value represents how many
multiples are underneath that number. so, the .8 means we're almost at another whole multiple,
but not quite - making the number of whole multiples simply 6.</p>
<p>It's 53, I think the easiest method is by counting, break it up into groups of ten starting with 40, multiply by 2 (since there's two of numbers that fit the formula in each group of ten) and then add 1 for 36 which wasn't counted originally.</p>
<p>haha.. i see the error I made. you do the highest and lowest possible value's. 7 & 59
1. 59-7=52
2. 52+1=53 (to include the number 7 itself)</p>
<p>oh, that's even better!
i only like mine because it's brainless, and it's not the worst method ever.</p>
<p>but you can know the answer for sure and not worry about endpoints if you do:
5x + 1 = 35 to 300
5x = 34 to 299
=> first possible multiple? 35
=> last possible multiple? 295
answer = (295-35)/5 = 53, case closed and no uncertainty.</p>
<p>although this would be tougher with other divisors that aren't so easy to spot by eye.</p>
<p>edit: goddammit, nevermind. (295-35)/5 = 52. just like with page numbers, if you're suddenly including the first number (or page) when counting in a range, you have to add one. 52+1=53.</p>
<p>edit 2: wow, way to reinvent the stone, me. i just repeated everything ach44 did above.</p>
<p>its 53...they always ask that type of question</p>
<p>for the question about the 2 lines that look soemthing like this...</p>
<p>3x + 6y = 6
2x + 4y = 4 </p>
<p>i put more than 3 because they were the same line</p>
<p>what about the readjusted average.. it was a grid in...</p>
<p>i said 6 ppl for that one</p>
<p>I am so sick of.....</p>
<p>myself.</p>