Question

Please check my work and correct me on the wrong ones

Answer 1

@Chicken_Nuggets_ #1, 4, 5, 9, and 10 are incorrect.

Answer 2

Since @BarbaraKara already helped you with #1, let's start with #4, shall we? Let me know whenever you're ready.

Answer 3

I am ready

Answer 4

#4). A bag has 5 red marbles, 6 blue marbles and 4 black marbles. What is the probability of picking a black marble, replacing it, and then picking a blue marble?

First of all how many marbles do we have in total? How many of these are black?

Answer 5

15 total and 4 black

Answer 6

Correct! thus what is the probability of selecting a black marble?

Answer 7

4/15?

Answer 8

Yes! Now you're replacing it, which means you're putting it back so then you would still have a total of 15 marbles. Agree? Now how many are blue and hence what is the probability of selecting a blue marble?

Answer 9

5 red so the probability would be 5/15

Answer 10

No sorry, I meant blue. I changed it. Read it again.

Answer 11

6/16

Answer 12

6/16? An extra marble was added?? Don't you mean 6/15?

Answer 13

No 6/15 sorry lol

Answer 14

Yes. So now what do you do to get the final answer?

Answer 15

Umm, multiply?

Answer 16

Yes so then what do get as the final answer. Reduce all final fractions to lowest terms.

Answer 17

(4/15)(6/15) = ??

Answer 18

8/75

Answer 19

Yes!

Answer 20

Thanks!

Answer 21

Now

#5). In how many different ways can Ally, Ben, Candy, Doug, Ed and Francis line up for lunch?

How many people need to be arranged to form a queue?

Answer 22

6

Answer 23

Correct! So how many ways can this be done, if the number of arrangements of n distinct members is given by n!

Answer 24

That's n factorial (n!)

Answer 25

120?

Answer 26

NO...What is 6 factorial? It's 6 X 5 X 4 X 3 X 2 X 1. What does that equal?

Answer 27

720!

Answer 28

Yes to 720. NOT 720 factorial. LOL

Answer 29

Lol alright

Answer 30

Next #9). John is choosing a password for his access to the internet. He decided not to use the digit 0 or the letter M. Each letter or number may be used more than once. How many passwords of 2 letters followed by 4 digits are possible?

So we have 6 positions to fill. 2 letters followed by 4 digits. Let's represent these positions with blanks.

_ _ _ _ _ _

First let's fill the first two blanks with the two letters. A letter can be used more than once. However, the letter M is not allowed. Excluding the M, how many letters are in the Latin alphabet?

Answer 31

26?

Answer 32

25 i mean

Answer 33

Yes! OK so then since a letter may be repeated, how many ways are there of choosing two letters?

Answer 34

25*2?

Answer 35

Is that 25 squared or 25 times two?

Answer 36

Times 2

Answer 37

Wrong. If the first position can be filled with any of the 25 letters, then there are 25 ways of performing this first action. Now for the second letter, also any of the 25 letters can be used, hence there are 25 ways of performing this second action. Thus there are
25 X 25 ways of picking two letters. Understand?

Answer 38

25 X 25 = 625

Answer 39

Nice work @calculusfunctions

Answer 40

Oh i see now

Answer 41

Now let's look at the four digits. Excluding the digit 0, how many digits are in the decinary system?

Answer 42

Thank you @BarbaraKara . Back at ya!

Answer 43

I dont know lol

Answer 44

How many digits do you use every day to represent an idea which is a number?

Answer 45

100?

Answer 46

What?? What digits do you use? A digit is a symbol which consists of a single numeral. 100 is not a digit. It's a collection of symbols or numerals which expresses the an idea (what we cal a number).

Answer 47

Im confused

Answer 48

Sorry, I don't mean to get philosophical. Please try again. How many digits are there in our decimal system?

Answer 49

Like 1-9?

Answer 50

1,2,3,4,5,6,7,8 or 9 ?

Answer 51

There are 10 digits. They are 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

Answer 52

Now if you exclude the zero, then that leaves nine digits. Understand?

Answer 53

Ok now im back to earth lol

Answer 54

Some we refer to our fingers as digits. You have 10 fingers, thus you have 10 digits.

Answer 55

OK so then if you use these nine digits, and a digit may be used more than once, how many four digit numbers are possible?

Answer 56

9^2 times 4?

Answer 57

9 squared times 4? Incorrect. You mean 9 X 9 X 9 X 9 or 9 to the fourth power.

Answer 58

so 6561?

Answer 59

So then 25 X 25 ways of placing the two letters and 9 X 9 X 9 X 9 ways of placing the four digits. Thus how many ways of placing the two letters and the four digits?

Answer 60

25 X 25 X 9 X 9 X 9 X 9 = ?

Answer 61

4,100,625!

Answer 62

Yes that is correct!

Answer 63

Alright cool

Answer 64

Alight now for the final question.

#10). What is the probability of rolling a 2 on a die and then re-rolling the die and getting an even number?

Fist what is the probability of rolling a 2 an a six-sided die?

Answer 65

1/6

Answer 66

Yes and then what is the probability of rolling an even number with the same die?

Answer 67

1/2

Answer 68

Yes so what do you get when you multiply these results?

Answer 69

1/12

Answer 70

Correct! So the the correct answer is D). 3/36 = 1/12. You see they tried to trick you in that last question, by not reducing the fraction.

Answer 71

Ahh i see it now, thanks so much for the help!

Answer 72

Welcome! Now I have to go. I think I burned the chicken nuggets.

Answer 73

BAHAHHAHAAHA ^^

Answer 74

LOL alright

Answer 75

@Macbass03

Answer 76

@Chicken_Nuggets_ Do you go to Keystone Online? I had that EXACT same problem.