SAT math question (Grid in)

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1

<p>Antonio applied to 13 colleges, listed below. Assuming that his chances of being accepted to each of the colleges are posted to the right of the corresponding college, what are the chances that he'll get accepted into at least one of them? (Disregard the % when gridding :D)</p>

<p>College A: 2%
B: 14%
C: 6%
D: 5%
E: 2%
F: 2%
G: 3%
H: 7%
I: 10%
J: 2%
K: 5%
L: 24%
M: 12%</p>

<p>question B: What are antonio's chances of being accepted in any one of the above, except college L?</p>

<p>thanks :D</p>

2

<p>add all together and divide my the amount of colleges. for b, don’t add L to the total and divide by (n-1) where n is the amount of colleges. i think that’s how you do it</p>

3

<p>I dont think so, that would just be the average of the percentages.
doesnt tell me what are my chances of getting into any one of the colleges</p>

<p>if ur answer were correct, then I would be correct in saying that if i had a 99% in one college and 1% in a million others, and in a bizarre world, they averaged out to 25%, then I would have a 25% chance of being accepted into one college?</p>

<p>a bit extreme, but it shows the flaw in your answer.</p>

<p>thanks anyway tho</p>

4

<p>Is this a College Board question?</p>

5

<p>^Are you serious?</p>

6

<p>what you do is write each percentage as a decimal and let each equal x sub-n</p>

<p>then, 1 - ∏(1 - x sub-n) * 100 equals the percent chance. For part B, disregard skip L for a value of n.</p>

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<p>

Why wouldn’t I be serious…?</p>

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<p>woohooo 64%</p>

<p>52% @ any one except L</p>

<p>things are looking bright</p>

<p>thanks buddy</p>

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<p>im confused…why can’t you just add all the percentages for (a)
and for (b) just subtract the percentage of L? O_o
because for (a) they don’t add up to a 100%…</p>

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<p>x sub-n??..</p>

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<p>2%- because the question is phrased " at least one of them" . It is the lowest percentage listed which is 2%</p>

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<p>Yeah, that’s what I was thinking… why would you need such complex math when it asks for just one, and you have it right in front of you.</p>

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<p>Yeah- it’s one of those trick questions that is a 10 second answer</p>

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<p>^ but wait, shouldnt it be the highest percentage? because you’re most likely to get into a college with a higher percentage, not with the lower…lol
and at least one of them is different than exactly into one…so i doubt 2% is right
it seems too low.</p>

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<p>no -it’s the lowest because the question is what is the chance you’ll get accepted into AT LEAST one of them. If the only college who accepts you is oone of the ones with a 2% chance then that chance is 2%.</p>

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<p>^^Yeah it’s 24% because then look at question B, it says besides college L, so then it’d be 14. You’d take the highest percentage because you have the best chance of getting into that college.</p>

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<p>All of the recent posters are wrong…the answer is 63% for A. This is likely not a CB question because it is quite difficult.</p>

<p>

</p>

<p>You either get into at least one college or NONE of them. So you find the probability of getting into none of them and subtract it from 1 (or 100%).</p>

<p>College A: 2% - 98%
B: 14% - 86%
C: 6% - 94%
D: 5% - 95%
E: 2% - 98%
F: 2% - 98%
G: 3% - 97%
H: 7% - 93%
I: 10% - 90%
J: 2% - 98%
K: 5% - 95%
L: 24% -76%
M: 12% - 88%</p>

<p>.98 * .86 * .94 * .95 * .98 * .98 * .97 * .93 * .90 * .98 * .95 * .76 * .88 = 0.365402299 = 36.54% chance you wil get into none of the colleges
100% - 36.54 % = ~63% chance you will get into at least one college</p>

<p>When you multiply probabilities (percentages) together, you find the probability of all the percentages in their simultaneous occurrence. So, by multiplying the probability of NOT getting into each college, you are finding the probability of not getting into ANY of the colleges.</p>

<p>e.g., (98% probability of not getting into college A) * (86% probability of not getting into college B) = 100(0.98*0.86) = 84% probability of getting into NEITHER college = 16% probability of getting into at least one of the two</p>

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<p>you guys are all wrong! The math I used was correct. Basically what it means is you take the chance of not getting into each one.</p>

<p>Then, multiply them all together—that’s the chance of not getting into any of them. Then do 1 minus that, and you get the chance of not not getting into any, which is the chance of getting into at least one.</p>

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<p>^isn’t that what crazybandit did? Except he used 100% isn’t of 1 when he subtracted.</p>

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<p>crazy bandit basically just copied what I wrote, but he must have typed it in before I was finishing responding</p>