viola

23 Questions
8 Answers

+2

528

2

+165

binomial

There are two parts to this question.

(a) Simplify n choose k / n choose k-1.
This is easy for me. I can expand n choose k and n choose k-1 and simplify to get (n-k+1)/k.
(b) For some positive integer n the expansion of read more ..

viola Jul 15, 2021

+2

425

4

+165

help

Find the constant term in the expansion of ( x^2 + 1/x )^4.

viola Jul 14, 2021

+1

435

1

+165

binomial stuff

Find the nearest integer to (2+sqrt(3))^4.

viola Jul 14, 2021

+1

403

1

+165

Marbles

John has seven red marbles and three blue marbles in a bag. He removes a marble at random, records the color, puts it back, and then repeats this process until he has withdrawn six marbles. What is the probability that exactly three read more ..

viola Jun 29, 2021

+1

430

3

+165

pascal thing idk

For how many integers n where 2<=n<=100 is n choose 2 odd?
Please don't leave an answer unexplained, it doesn't understand me help the problem.

viola Jun 22, 2021

+2

457

2

+165

Help (again)

Sorry for posting twice in sucession, I was going to add this question in the same post as my previous one, but somehow forgot. Also, if you aren't going to explain an answer, I won't learn and I might as well not have the answer anyway. (I'm looking at read more ..

viola May 23, 2021

+2

447

4

+165

help

A Senate committee has 5 Democrats and 5 Republicans. In how many ways can they sit around a circular table if each member sits next to two members of the other party? (Two seatings are the same if one is a rotation of the other.)

viola May 23, 2021

+2

1331

4

+165

Help is appreciated

Our club has 25 members, and wishes to pick a president, secretary, and treasurer. In how many ways can we choose the officers, if individual members are allowed to hold 2 but not all 3 offices?

(if you give an answer always explain read more ..

viola May 1, 2021

+2

478

3

+165

help me

We call a number peachy if every digit in the number is either a 3 or next to a 3. For example, the numbers 83 and 131 are all peachy, but the numbers 304 and 31653 are not peachy.
How many positive 2-digit numbers are peachy?
read more ..

viola May 1, 2021

+2

875

1

+165

Help would be appreciated

(Please give more than just an answer, because I want to understand the problem)

How many 3-letter sequences can be formed if the second letter must be a vowel (A, E, I, O, or U), and the third letter must be different from the first read more ..

viola Apr 23, 2021

+2

681

2

+165

I need help

A regular octahedron is made up of eight equilateral triangles, each with side length one unit, as shown below. An ant starts at the top vertex, walks along the edges of the triangles without ever traversing the same edge twice, and ends at the top vertex. read more ..

viola Dec 7, 2020

+3

578

1

+165

help

What is the maximum number of consecutive positive integers that can be added together to create a sum less than 400?
(I am sure it is not 378)

viola Oct 28, 2020

+1

571

1

+165

help no troll guest pls

Let R be the circle centered at (0,0) with radius 10. The lines x = 6 and y = 5 divide R into four regions R1, R2, R3, and R4. Let [Rnumber] denote the area of region Rnumber. If [R1]>[R2]>[R3]>[R4],then find read more ..

viola Aug 28, 2020

+165

+2

I see. Thanks to you and cPhill. I hope you all have a nice day!

violaJul 14, 2021

+165

+2

I'm sorry, but could you explain your answer?

violaMay 23, 2021

+165

+3

Well, I just figured it out myself o_o
thanks anyways cphill!

violaMay 1, 2021

+165

+1

Image

violaDec 7, 2020

+165

+2

Yeah, thanks to all who actually helped!

violaAug 26, 2020

+165

+2

I dont even know how you came up with that c**p

violaAug 19, 2020

+165

+3

Nevermind, I found the answer myself!

violaAug 6, 2020

+165

+3

Thank you! :)

violaAug 4, 2020