HI
I have a question on coins and its really stressing me out.
Here it is:
A coin is tossed 8 times and the outcomes are recorded in a row.
How many of these have equal number of heads and tails?
According to my book, the answer is 70. I have been through calculations but none of them gave 70.
So would you help me on that? . Thank you very much.
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Thanks Shifa!
I have four medications each with four different dosages. I want to mix three medications and also four medications using all possible dosages. How many permutations will I have using three medications and how many will I have using four medications? Can someone help me with this please?
I usually see the question asking for example: how many ways to arrange the letters in the word CHAIR? I know it is 54321=120 but I have never seen the question asking how many ways to arrange the letters in the word ENTER, for example. Would you please explain it for me. Thank you very much.
Thanks! Helping my son with 6th grade math…wish you were his teacher!
or at least had written his textbook.
Hi there!
I’m studying for a test and I was wondering if you could give me a hand with the following questions:
How many different 4 letter combinations can be made from the word SUCCEED?
I read your example earlier, where you treated it as if the doubles were different and then subtracted cases. But this time there are two sets of doubles which seems to complicate matters.
I thought I had finally found a solution by manipulating the combinations formula.
Since Combinations = (# of permutations ) / ( # permutations of objects picked)
I used the doubles formula for permutations ( 7P4 / 2! 2!) and then divided this by 4!.
But this got me a decimal answer. (8.75)
I tried it a few other ways too, usually getting answers between 10 and 30.
The textbook says the answer should be 230!!!
I even tried listing the possible combinations, but can’t see it ever getting that high. Ack!
Also, if a question asks how many different amounts I can make from 3 quarters, 2 loonies and 4 toonies…what is the easiest way to eliminate the cases where the two loonies will equal the same amount as a single toonie?
Any help would be greatly appreciated!!
Thank you so much!!!
Can anyone answer this ques:
Find the no. of ways u can fill 3x3 grid(with 4 corners defined a,b,c,d) if u have 3 white marbles and 6 black marbles??
you must be a genus or something.are u a professor of mathematics or what?
Good post. I am experiencing some of these issues as well.
.
Do you have any other info like this but with & without replacements, rules of sum & so on? Thanks!
hi,
can any one help me with the following problem please-
what is the total number of way N numbers can be picked such that the sum of the numbers is equal to S where the numbers can be from 0 to (s/2) ,repeatable and sequence dependent.
Thanks for any help.
Hi,
sorry if posting twice but I really need help in finding this
How many ways N numbers can be picked such that there sum is equal to S where the numbers can be from 0 to (S/2),numbers are repeatable and order dependent.
thanks for any help
i have tow question and i need answer—>
Consider abox that contain 3 red,4 black and 2 white balls if tow balls are drawn from the box,one at a time with replacment,the probability that at least one of the tow balls is black
if three balls are drawn together from the box,the probability the exactly one of three balls is black is:
there are 9 teams playing criket match aginst each other twice so what will be number of matches will be played and only top 4 team will qualify to play semifinal and final ?so,how many minimum matches the top 4 team has to win to qualify for semi and final.
hi I like this site very much …
I have one Question …
how could we find that , the given problem is of permutation or combination ? is there any ‘keyword’ ?
thanks…
3English , 4 History class
you need to select 3 classes
for each selection at least one should be english
so there are 3 cases
add 1)+2)+3) will give answer
Please check if its correct
The next logical step from above is - you give those 8 people 3 contests and award the winner of each with a can. In this case, it is possible for one person to win more than one prize. But we don’t care the order of the prizes. (If this has already been pointed out I missed it.)
I could say that 8x8x8 is the total number of ways to distribute the prizes, and divide out the dupes (AAB = ABA etc) or I can realise this is the 3 single-prize count (which we got) + the 2-prize count (where one of the prizes is 2 cans) + the 1-prize count (the prize is three cans - luck-ee) which is 8.
But I want to derive the “combination with repeats” formula.
@Carrie: in the first version, you use combinations on each of the book types - since they can be disordered amongst themselves - add them up: that’s how many ways to stack them in one order. Multiply that by the number of different ways to order the subjects on the shelf.