dad

You have 1000 coins. The probability of a coin being fake is 1% so you can expect there to be 10 fake coins (the number could be bigger or smaller, disregard that).

You decide to divide 1000 coins into 50 batches of 20 coins each. What percentage of the batches will contain at least 1 fake coin?

I am stumped by the part 'percentage of 50 batches' . Should we treat this is a binomial problem , or not.

For one batch of 20 coins, the probability the batch contains at least one fake  1 - ( 1- 1/100)^20 or is 0.18289. But how does that help us with the 50 batches.

You have 1000 coins. The probability of a coin being fake is 1% so you can expect there to be 10 fake coins (the number could be bigger or smaller, disregard that).

You decide to divide 1000 coins into 50 batches of 20 coins each. What percentage of the batches will contain at least 1 fake coin?

I am working on Poisson distribution problems and then i have this problem which I am stumped.

"Plane crashes occur at an average rate of 2.5 per year. If there has not been any crashes for the first nine months, given this information, what is the probability that there will not be any crashes this year? Note! Let X represent the amount of time (in months) for a plane crash. You may use R to help you evaluate. " 

I can't tell if its poisson or if its exponential, or the teacher was having a derp moment.

This code is not doing what I am expecting it to do.

I posted it on paste bin https://pastebin.com/A82ymCmU

In line 15 , for some reason in the do loop, the if statement is not executing correctly,clearly  a[0][2] < a[1][2]  is false if i choose m = 83, n =38.

The point of this program is to calculate the euclidean algorithm.  Specifically find coefficients 83x + 38y = gcd(83,38).

That's not important, i am more concerned why the matrix is not working.

Question from Book:

What symmetry property does the word “zoonosis” have when written in uppercase letters?

Answer from Book: It is symmetric under a horizontal reflection.

This seems wrong. If we reflect ZOONOSIS horizontally we don't get back ZOONOSIS, the Z, N, and S are facing the wrong way.

Name of book is Contemporary Algebra by Joseph. A Gallian, Eighth edition.

Question from Book:

What symmetry property does the word “zoonosis” have when written in uppercase letters?

Answer from Book: It is symmetric under a horizontal reflection.

This seems wrong. If we reflect ZOONOSIS horizontally we don't get back ZOONOSIS, the Z, N, and S are facing the wrong way.

Name of book is Contemporary Algebra by Joseph. A Gallian, Eighth edition.

300 mLs of a 2% NaOH (sodium hydroxide, a base) solution are mixed with 200 mLs of a 1% H2SO4 (sulfuric acid) solution.

NaOH + H2SO4 ----> H2O + Na2SO4

a) who is the limiting reagent?

b) who is the leftover reagent, and how much is left over (in moles)

c) how much products (water and salt) are made (in moles)

d) estimate the pH after the reaction is done

e) the molarity of the salt (Na2SO4) in the final solution

I am stumped by this question. How to solve it without knowing the density of each solution, and that varies by temperature?

I balanced the equation

2 NaOH + H2SO4 → 2 H2O + Na2SO4

molar masses:

NaOH:  39.997 g/mol

H2SO4:  98.07848 g/mol

H2O: 18.01528 g/mol

Na2SO4 :   142.04213856 g/mol

How many different combinations of marbles can you pick from a bag containing 3 blue marbles 4 green marbles and 5 red marbles. A

ssume you must take at least one marble.

I am thinking this is a combinations problem. And we have to count

# ways 1 marble

#ways 2 marbles

.... # ways 12 marbles

If the scale factor of a particular model train is

1:48 and the model is 8 inches long, then

how long is the actual train in feet?

If the model train weighs 1/2 a pound, how much

would the actual train weigh?

For the first part I got 48/1 * 8 / 12 = 32 feet.But the second part I don't think is correct.

48 * 1/2 pound * 48 = 24 pounds.One of these is incorrect. I was thinking maybe  it should be 48^3 * 1/2 because weight is related to volume ?

You drop a large rock from a 19 story building.  It is 78 meters high. The wind is blowing from the southwest at 3.5 m/s.   

A. What is the initial velocity of the rock?

B. How long will it take to hit the pile of leaves that are sitting below?

I am confused, does the wind have an effect on the kinematic equations.

Three particles A,B and C are situated at the vertices of an equilateral triangle ABC of side a at=0. Each of the particles moves with a constant speed v. A always has its velocity along AB , B along BC and C along CA . At what time will these particles meet each other?

I dont understand this question because it seems that the particles are restricted to the sides of the triangle, and are always moving away from each other.

There is a solution here, but I don't understand it. https://doubtnut.com/question-answer-physics/three...

You are working on a word puzzle and are looking for 4 letter 'scrambles',

or permutations, from the word CALCULATOR.

For example CUTR is a 4 letter scramble.

How many ways can you scramble the letters.

My work: I tried to use the formula nPr, but there are repetitions

in the word CALCULATOR,  which is AACCCLLORTU , so we can't use 10P4. What about 10P4 / (2! 3! 2!). I don't think that makes sense.

Rory and Luke are playing in the final of a matchplay golf tournament. On the first hole, they each have a ten foot putt for birdie.The probability that Rory makes the putt is 0.8 and the probability that Luke makes the putt is 0.7, and these events are independent. Assume that neither player will take more than two putts to complete the hole. The probability, to the nearest hundreth, that Rory wins the hole is ?

The probability, to the nearest hundredth, that neither player wins the hole is?

I chose "thick outside border" for a column of numbers and the first row will not show the top border. The top border will only appear if I drag the column of numbers a cell down. I posted a screenshot here. The border is red: https://snipboard.io/OxUdbo.jpg

If we think of the picture nails as slots

we have

___ ___ ___ ___ ___ ___ ___

1 2 3 4 5 6 7

There will be two blank slots.

A full 300 gallon water tank is initially 70° F. How long will it take the tank to reach 60° F if 10 gallons of water is being replaced every minute and the replacement water is at 55° F and it increases 0.16 degrees per gal, per min.

I want to attempt it using Newton's Law of cooling but I am not sure how to go about that. Or should I approach it as a first order differential equation mixing problem.