Posted on 15 December 2016 - 02:58 PM
JK JK ily and props to getting thisPosted on 15 December 2016 - 02:59 PM
-.- probability, permutations and combinations was the easiest thing I've ever done in alg II lolPosted on 15 December 2016 - 03:01 PM
SamU1 wrote
Unwise wrote...
Sam ily
Posted on 15 December 2016 - 03:16 PM
Purpkey wrote
Radioactivebeans wrote...
It can not actually be a two digit letter, for example if you take the letters A B C D and find out how man permutations there are with them there are 60. Repetition has more letters than the simple 4 so it would essentially be a higher number. Repition has actually 10 letters so the equation would have to be 10P10 and we have two o's and two I's so it would be (2*2). The next step is (9*8*7*6*5*4*3*2*1) (2*2) = (9*8*7*6*5)/(2*2) since other numbers cancel out. Then you would have 27,360. Then multiply it by ten since thats the number of letters within the words to get 273,600. You would then divide by 4 to get 68,400. That is the answer
Posted on 15 December 2016 - 03:19 PM
Unwise wrote
2. Ternary strings are strings of numbers where each number is either 0, 1, or 2. With length four, you should have 3^4, or 81, total strings. This is gonna get a bit hairy, so I'll write everything out as clearly as possible.
One third, or 27 strings, will start with 1. Of those, 9 will have another 1 immediately after, fulfilling the requirement. Of the 18 that don't, 6 will have a 1 as the third number, and of the 12 who don't, 4 will have it as the fourth. So out of the 27, 19 will fulfill your requirement.
Looking for an even easier way to say this? Out of the strings starting with 1, the odds that they won't have a single additional 1 in the string is (2/3)^3, or 8/27, which conveniently says 8 of the 27 strings won't fulfill the requirement. 19+8=27, which chelps double check my answer.
Now, for the other 54 strings. Of these, another third, 18, will have 1 as the second number. Of those, 6 will have 1 as the third, and of those who don't, 4 will have it as the fourth. This is again verifiable by doing (2/3)^2*18=(4/9)*18=8. and 18-8=6+4=10.
For the final 36 strings which have a 0 or a 2 in both the first and and second slots, only the ones with 1 in both the third and fourth slots can fulfill the requirements, at a chance of 1/9, giving four total strings. We can even write out these strings: 0011, 0211, 2011, 2211.
For the final answer, 19+10+4= 33 total strings.
3. Repetition has 10 letters. This would mean it would have 10! permutations, but it also has 3 sets of double letters, meaning any sets with the same double letters would be indistinguishable, so you divide by 2!^3=8. This comes out to 10*9*7*6*5*4*3*2, or a clean 453600. Your answer for this above is incorrect.
4. Not entirely sure what you're asking here (and I really don't want to do a formal proof on here). But if I'm understanding what you're saying correctly, this is a direct extension of what I did in problem 6 - essentially, for a graph to be finite, you need to have either entirely even vertices or two odd vertices which sum to an even total - but I don't know enough graph theory to be sure of what you mean, or how the situation with a single odd vertex plays out.
5. I'm sure its possible, but I don't really see the point in finding the exact string.
6. This is mainly common sense (and I don't feel like doing a formal proof once again) - but basically, with vertices of even degrees, you enter and exit each vertex the same number of times, creating a Eulerian cycle. If you have vertices with an odd degree, you leave or enter them once more than you do the other. This means you have to designate one as your starting point and the other (if you have two) as your ending point. If you have more than two, you can't designate additional starting/ending points, and you will either "get stuck" in one or never reach it the final time.
Purpkey wrote...
This answer is correct, but simply in scientific notation.
^
Posted on 15 December 2016 - 06:44 PM
Purpkey wrote
Radioactivebeans wrote...
It can not actually be a two digit letter, for example if you take the letters A B C D and find out how man permutations there are with them there are 60. Repetition has more letters than the simple 4 so it would essentially be a higher number. Repition has actually 10 letters so the equation would have to be 10P10 and we have two o's and two I's so it would be (2*2). The next step is (9*8*7*6*5*4*3*2*1) (2*2) = (9*8*7*6*5)/(2*2) since other numbers cancel out. Then you would have 27,360. Then multiply it by ten since thats the number of letters within the words to get 273,600. You would then divide by 4 to get 68,400. That is the answer
What grade are you in???
Last edited on 15 December 2016 - 06:47 PM by MeMyselfAndCube
SamU1 wrote
Unwise wrote...
Posted on 15 December 2016 - 06:50 PM
Intimidated wrote
Purpkey wrote...
What grade are you in???
11th
Posted on 15 December 2016 - 07:22 PM
Purpkey wrote
Intimidated wrote...
11th
HA I GUESSED IT! For some reason when I clicked on this notification I immediately thought 11th grade
Posted on 15 December 2016 - 07:24 PM
I'll be right back, I am going to ask those questions to my really smart uncle. His name is Uncle Google. He knows everything about everything.Posted on 15 December 2016 - 07:28 PM
Intimidated wrote
Purpkey wrote...
HA I GUESSED IT! For some reason when I clicked on this notification I immediately thought 11th grade
Congrats
Posted on 16 December 2016 - 08:16 AM
Unwise wrote
Jesus Christ.
Posted on 16 December 2016 - 10:02 AM
Some people join Badlion to get high ratings while other join to solve maths/science questions. LOOL