2c maTh probs-MATH WIZZES HELP

Test Preparation
1

<p>First one :
How many different ways can you distribute 7 identical apples to three people?(show method please)</p>

<p>Second one:</p>

<p>f(x)=sin(cos(x)) …what is f(250 degrees)…seems obvious right…well for some reason u get different answers when u use degrees and then converted radians(in their respective modes on th calc) ■■■</p>

<p>thrid one: i dunno seems OBVIOUS A plant whose height is 25 inches at the end of 21 st of October grows at the same a constant daily rate and becomes 26 inches tall at the end of 22nd of October. How tall will the plant be at the end of 31st of OCtober???</p>

2

<p>7 apples 3 people
hmmm… tough one…</p>

<p>maybe use permutations…</p>

<p>start by making a table for each persons possible number
p1 01234567
p2 01234567
p3 01234567</p>

<p>you can see that for the total there are 21 options…of possible choices
now you can only pick 3 of those…
so you use permutations
N nPr R where N=21 R=3 (you must have a graphinc calc)
but this results in 7980 divide that by 7 i think oh gosh… i can’t do it… hope thats not a real question…</p>

3

<p>i’d say brute force drawing a bunch of tables could probably solve this problem in about 2 minutes…</p>

4

<p>Second one: omg 250deg does not equal 250 radians</p>

5

<p>beramod …OBVIOUSLY! 1 degree=pie/180 radians </p>

<p>but try using 250 degrees…in degree mode on ur calculator for the equation and u get -.006
then use radians (250(pie))/180…in radian mode in ur calculator for the equation and u get -.3354
***i thought they should be the same answer just like how sin pie is the same as sin 180 degrees</p>

<p>answers APPRECIATED FOR ALL PRBS</p>

6

<p>nm i got it…but my question is then why do u have to do it radians…not degree mode</p>

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<p>actually nm…id ont get it …i need somebody like feuler to explain!!! also the other as well</p>

8

<p>okay the reason you must do it in radian mode is because the answer is in radians not DEGREES!!! lol… you could do it in degrees then convert to radians…
its like some one asks how fast does this car go… and you say 100000343 nanometers/sec
obviously the desired unit is km/h or mph not nm/s same logic applies here… you must give them the unit they desire…</p>

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<p>The solution to teh first question is 7 C 3.</p>

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<p>i thought it was 7c3…but the “practice test” says its (9ncr2)…don’t knw where they came up with that…</p>

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<p>acutally i m not even sure if that was the answer…can any1 solve this probability problem!!!</p>

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<p>ANY1 solve this problem</p>

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<p>Let m, n, and p be the number of apples given to each person respectively.
m+n+p=7.</p>

<p>Look at the following possible values of m, n, and p.
m|n|p
0|0|7
0|1|6
.
0|7|0
Total of 8 possibilities if m=0</p>

<p>m|n|p
4|0|3
4|1|2
4|2|1
4|3|0
Total of 4 if m=4.</p>

<p>m|n|p
6|0|1
6|1|0
Total of 2 if m=6.</p>

<p>It is apparent if m=i<8, the number of possible combinations is 8-i
So the answer is 1+2+3+…+8=8*9/2=36.</p>

14

<p>Wouldn’t number 1 be 7 nPr 3. You have 7 <i> identical </i> apples, thus, order has no significance. You have to distribute those 7 apples to 3 people… 210 (?)</p>

<p>Or simply 7 * 6 * 5 = 210</p>

<p>First apple has 7 possibilities. Second person can get one of six apples. Third follows the pattern (5 possible apples). It has to be right, no?</p>

15

<p>it’s just 7C3 :)</p>

16

<p>I’m fairly sure averagemathgeek is correct.</p>

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<p>yeah averagemathgeek is right somehow…the answer was like 9ncr2</p>

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<p>could u elaborate averagemathgeek…explain it more simply to me</p>

19

<p>dam i got it…ur good mathgeek. thanks alot</p>

20

<p>is the first problem likely going to be on the test? Very hard</p>