<p>what is xiggi's formula... sry, noob question</p>
<p>When the ratio of the two speeds is simple, like the 4:1 here, there's another easy way to do these in your head: 4/5ths of the hour was on the bike and 1/5 on the bus. There's no reason to even mess with minutes.</p>
<p>4/5hr * 5 miles/hr = 4 miles </p>
<p>It seems that there are lots of approaches that are pretty good at getting you to the answer quickly. It just depends on which is familiar and natural to different people.</p>
<p>^^^ Correct, marathonman, as I described in post # 8. So, either way, doing the 1/5, 4/5 or the quick "reasoning", no fancy shmancy multistep d=rt (or whatever) is necessary.</p>
<p>there was a xiggi formula question the fill in's today thank u xiggi made that question a whole lot easier</p>
<p>^MetsFan09 --- yep, there was this question today, and all it took was punching in 2<em>20</em>40/(20+40) on your calculator to get the answer.</p>
<p>I could not help but yell "I can't ... believe it!" when I saw that question.</p>
<p>xiggi did not invent the formula, but he deserves a huge credit for steadfastly recommending it to the CC community.
Thanks, xiggi!</p>
<p>Can we finally put this never-ending discussion (xiggi-way or my-way) to rest and shut the lid?</p>
<p>Before the lid is nailed, let me squeeze in one last comment.:D
As I very recently mentioned on the other tread, how do you reason your answer if there are no answer choices - just like in today's question (it was a grid-in)?
Gotta get your hands dirty with the stinkin' formula.:)</p>
<p>Thank you, GCF.</p>
<p>gcf -
You can "reason" the answer when you are looking at the possible choices, but I also think you can figure out the distance w/o the choices. No matter.
And what other "tread" are you referring to??</p>
<p>JYM, in the end, everything boils down to ... reasoning. Isn't that why the test name is currently SAT Reasoning Test. Isn't it amazing that the average speed questions (which are always ranked among the hardest on the test) can be solved in seconds? In the case of a multiple choice, a tester ONLY needs to verify the exact text of the question to pick the correct answer. </p>
<p>In the case of student produced answer or grid-in, the 5 seconds answer is not available, but it does not take a lot longer to write down the correct answer. In this case, it would have been about 12-15 seconds. Not bad for the "hardest" grid-in question.</p>
<p>Of course, all of this is where knowledge of the test blurries the lines of reasoning and aptitude. A well-prepared student does not turn into a robotic test taker, but into a test taker who uses a bit of knowledge and a lot of reasoning. That is why the test is not about learning formulas and tricks, but about knowing how and when to apply them, or even better how to recreate them on demand.</p>
<p>^^^ Couldn't agree more, xiggi. My whole point was that it was, IMO, easier and faster to just think about the question for a second and quickly figure out which choices could easily be eliminated. It didn't require that multi-not-quite-15 step calculation. In fact it didn't take any calculation-- 3 of the answers just didnt make intuitive sense. To me, the more steps in a formula, the more one runs the risk of making a careless math error. I am not referring to your 2(a*y)/x+y (didn't know the "method"). I am just saying that sometimes you don't need a racehorse to pull a milkcart.</p>
<p>what was the answer to this sat question? 30 right?</p>
<p>^^jym626
Having the last word does not automatically make it the right on.
[Proofreading optional]</p>
<p>^Leetxy
no 30, sorry. (20+40)/2 would be too easy. It's
[quote]
2<em>20</em>40/(20+40)
[/quote]
</p>
<p>Getting a little megalomaniac, ain't I, with quoting myself and everything... =D</p>
<p>gcf-
so why did you feel the need to get in the last word? :) This isnt a matter of right or wrong-- just different ways of skinning this cat. Sheesh</p>
<p>gym-
I did not imply that my last word was the right one.:)
This cat must have had not just nine lives - nine skins as well.:D</p>
<p>gcf-
Small request -- would you mind not calling me "gym" unless you are referring to my physique :)</p>
<p>I don't understand- why the formulas? You don't even need to use math to do this problem. </p>
<p>If she's going 5 miles an hour, obviously C, D, and E are wrong right off the bat, since that would mean she was cycling for one hour or more and wouldn't have time to return to her original location by bus. That leaves A or B. </p>
<p>If she only cycled (A), 2 miles, (24 minutes), then that means it took 36 minutes to go two miles on a bus going 20 mph (obviously NOT!). </p>
<p>You can stop right there and bubble in B, unless you want to eat up more test time.</p>
<p>Edit: Sorry, I wasn't able to read all the pages in this thread because of error messages. I just managed to finagle my way into page two and I see someone already went through this thought process.</p>
<p>Yup- doubleplay-- thats exactly what I said in posts # 6, 20, 23 and 28. Maybe we are seeing a difference in how the parents vs the kids view this stuff? I don't recall having the formulas and strategies now available to people prepping for the SAT (aside, of course form the basic math formulas we learned in school). We were less about "strategy" and more about problem solving perhaps??</p>
<p>This reminds me of the preamble to Tom Lehrer's song "New Math"
...but in the new approach, as you know, the important thing is to understand what you're doing, rather than to get the right answer
</p>
<p>though based on the song, the answer could be B or E if E were in base 4 and B is in base 10.</p>
<p>Overall, it seems to illuminate the difference between "preparing for the SAT" and "preparing to receive an education" in much the same way that there's a difference, once at college, between "getting a degree" and "getting an education."</p>
<p>I am always amazed and amused how easy it is for some to offer explanations to a correct answer AFTER the correct answer is spotted. </p>
<p>Should we speculate about the time it might takee the posters who do not understand why math is needed to correctly answer the same problem as a GRID IN? Or even find the answer!</p>
<p>
[quote]
Lado rode her bicycle to the repair shop and rode the bus home by the same route. Excluding the time she spent at the shop, she spent a total of 1 hour traveling from her home to the shop and back again. If she rode her bicycle at an average speed of 5 miles per hour, and the bus traveled at an average speed of 20 miles per hour then for how many miles did she ride her bicycle?
[/quote]
</p>
<p>So....multiple paths to the same place are a bad idea?</p>