Answer:
The perfect square lockers are the only ones left open.
Step-by-step explanation:
Here is a legit link to an explanation of this old puzzle problem!
https://36university.com/act-math-locker-problem-solution/
Quoting from that page:
Method 2: Who Touches Which Lockers
Identifying which students touch which lockers is a little less of a brute-force approach and would likely have gotten you to the solution a little more quickly.
Here’s what I mean:
Consider locker #1. The only student who touches locker #1 is student #1. Student 1 opens the locker, and since no one else touches it, it will be left open at the end.
Consider locker #2. Student 1 opens the locker, and student 2 closes it. No one else touches the locker, so it will be closed.
Consider locker #10. Students 1 opens the locker. Student 2 closes it. Students 3 and 4 skip right by it. Student 5 opens it. Students 6, 7, 8, and 9 skip right by it. And student 10 closes it. Locker #10 will be closed.
Mental Milestone 1: After looking at several lockers, you should notice that lockers are only changed by student numbers that are factors of the locker number. In other words, locker 12 is changed by students 1, 2, 3, 4, 6, and 12.
Mental Milestone 2: You should also have noticed that factors always come in pairs. This means that for every student who opens a locker, there is another student who closes it. For locker #12, student 1 opens it, but student 12 closes it later. Student 2 opens it, but student 6 closes it later. Student 3 opens it, but student 4 closes it later.
By this logic, every locker would be closed.
But there are exceptions!
Consider locker #25. Student 1 opens it. Student 5 closes it. Student 25 opens it. The locker will be left open, but why? In this case, the factors do not come in pairs. One and 25 are a pair, but five times five is also 25. Five only counts as one factor. This causes the open-close pattern to be thrown off. Locker #25 is left open.
Mental Milestone 3: When factors don’t come in pairs, the locker will be left open. And factors don’t come in pairs when numbers are multiplied by themselves. Perfect squares (1, 4, 9, 16, 25, 36, 49, 64, 81, 100,…) are the only numbers whose factors don’t come in pairs because one set of factors, the square root, is multiplied by itself. This means that only perfect square lockers will be left open.
Locker #s 1, 4, 9, 16, 25, 36, 49, 64, 81, and 100 are left open!
The volume of a cube is 496cm
Work out the length of its side rounded to 1 DP
cm
Answer:
7.9
Step-by-step explanation:
Volume = side · side · side
∛496 = 7.915783219
Helpppppppppppppppppppp
Answer:
x = -5
Step-by-step explanation:
f(x) = [tex]\frac{x+5}{4}[/tex]
Okay, so in order to find the zeroes of the equation, we need to find the values of x for which f(x) = 0.
[tex]\frac{x+5}{4}[/tex] = 0
We can start by multiplying both sides by 4. Anything multiplied by 0 equals 0, so we have the following:
x + 5 = 0
Now, subtracting 5 from both sides in order to isolate x, we have:
x = -5
To check our work, let's substitute -5 into our equation:
f(-5) = [tex]\frac{-5+5}{4}[/tex] = [tex]\frac{0}{4}[/tex]
0 divided by anything equals 0, so f(-5) = 0.
-5 x -0.2 i got stuck here
[tex]\sqrt{5}+\sqrt{5}=?[/tex]
[tex]\sqrt 5 + \sqrt 5 \\\\=\sqrt 5(1+1) \\\\= 2 \sqrt 5[/tex]
..................................
7. Proving the Perpendicular Bisector Theorem Using Reflections
Given: Point P is on the perpendicular bisector m of AB.
Prove: PA PB
The nth term of a sequence is n^2 + 5.
Find the first three terms and show that 261 is a term in this sequence.
Answer:
first 3 terms: 6, 9, 14
16^2+5=261
Step-by-step explanation:
1^2+5= 6
2^2+5= 9
3^2+5= 14
What is the graph of y=3/4x-3
Answer:
the answer is graph C
Step-by-step explanation:
babyface_wee
Answer: Graph A
Step-by-step explanation:
y-intercept = -3 So, Not Graph B
Slope = 3/4x = rise 3 run 4 or up 3 right 4. So not Graph C
Graph A meats all the criterias.
1 define and give an example for: rate:
2 define and give an example for unit rate
pls help I'm struggling
Step-by-step explanation:
1. quantity, amount, or degree of something measured per unit of something else her typing rate was 80 words per minute. b : an amount of payment or charge based on another amount specifically : the amount of premium per unit of insurance.
2.A unit rate means a rate for one of something. We write this as a ratio with a denominator of one. For example, if you ran 70 yards in 10 seconds, you ran on average 7 yards in 1 second. Both of the ratios, 70 yards in 10 seconds and 7 yards in 1 second, are rates, but the 7 yards in 1 second is a unit rate
What are numbers that add to 50 and subtract to 10
Answer:
30 plus 20 is 50
30 minus 20 is 10
If you and 2 friends went to dinner and the bill was $57.90 after taxes and you wanted to leave a 25% tip. How much total would you have to pay each? (round to the nearest hundredth)
Answer:14.48
sorry if it is wrong.
Step-by-step explanation:0.25*57.90=14.475
Which fraction is larger? 2/3, 3/4, 3/5, 5/7
A: 2/3 B: 3/4 C: 3/5 D: 5/7
The cost of a pen is 3 times the cost of a pencil. The total cost of 8 pencils and 5 pens is $11.50.
Please help me to find the costs of a pen and a pencil.
Answer:
$5.78
Step-by-step explanation:
brainliest?
A unit cube could be 6 units long by 6 units wide by 6 units tall. True or false?
Answer:
True
Step-by-step explanation:
Solve the system of equations by substitution.
3x + y = 9z
-5x + 2y = -4z
What is the value for y from the first equation, that could be substituted into the second equation?
-9z + 3x
3z + 9x
9z - 3x
-3x - 9z
Answer:
x = 1.27
y = 5.18
Step-by-step explanation:
to solve this system of equation by simultaneous equation we say that let
3x+y=9.............................. equation 1
-5x+2y=4 .......................... equation 2
from equation 1
3x+y=9.............................. equation 1
y = 9 -3x.............................. equation 3
substitute the value of y = 9 -3x into equation 2
-5x+2y=4 .......................... equation 2
-5x + 2( 9 -3x) = 4
-5x + 18 - 6x = 4
collect the like terms
18 - 4 = 6x + 5x
14 = 11x
divide both side by 11
14/11 = 11x/11
x = 14/11
x = 1.27
put the value of x = 1.27 into equation 3
y = 9 -3x.............................. equation 3
y = 9 - 3( 1.27)
y = 9 - 3.82
y = 5.18
to check if you are correct put the value of x and y into either equation 1 or equation 2.
3x+y=9.............................. equation 1
3( 1.27) + 5.18 = 9
3.81 + 5.18 = 9
9 = 9
0.314 x 100 = help me pls
Answer:
your answer would be 31.4 :)
Step-by-step explanation:
Old Faithful in Yellowstone National Park shoots water 60 feet into the air that casts a shadow of 42 feet. What is the height of a nearby tree that casts a shadow 63 feet long? Assume the triangles are similar.
what is the slope of (10,8) and (1,9)
Answer:
1/-9 or -0.111(repeating)
Step-by-step explanation:
Answer:
(1,9)
Over to the right one. then up nine of a graph
Write a recursive formula for the explicit formula
A(n) = -1 + (n-1)(-2)
Answer:
see explanation
Step-by-step explanation:
A recursive formula allows a term in the sequence to be found by adding a common difference to the previous term
Given the explicit formula
A(n) = - 1 + (n - 1)(- 2)
This is an arithmetic sequence with explicit formula
A(n) = a₁ + (n - 1)d
where a₁ is the first term and d the common difference
For the given explicit formula, then
a₁ = - 1 and d = - 2
The recursive formula is then
[tex]a_{n+1}[/tex] = [tex]a_{n}[/tex] - 2 ; a₁ = - 1
find the slope of the line, given the points (0,2) and (3.6,2) show all your work
Answer:
There is no slope because the slope is zero. The line has no slope because it's a vertical line.
Step-by-step explanation:
Slope = [tex]\frac{2-2}{3.6-0} = \frac{0}{3.6} =0[/tex]
Slope = 0
The line has no slope.
A company is considering purchasing the mineral rights to two different mountains. The probability that it will purchase the mineral rights to the first mountain is 0.55. The probability that it will purchase the mineral rights to the second mountain is 0.4. Assuming the decisions to purchase the mineral rights to each mountain are made independently, what is the probability that it will purchase the mineral rights to exactly one of the two mountains?
a. 0.4
b. 0.45
c. 0.51
d. 0.49
Using probability of independent events, it is found that the probability that it will purchase the mineral rights to exactly one of the two mountains is given by:
c. 0.51
If two events, A and B, are independent, the probability of both happening is the multiplication of the probability of each happening, that is:
[tex]P(A \cap B) = P(A)P(B)[/tex]
In this problem, these following two events result in the rights of exactly one of the two mountains being bought:
First bought(0.55 probability), second not(0.6 probability).First not bought(0.45 probability), second bought(0.4 probability).Hence:
[tex]p = 0.55(0.6) + 0.45(0.4) = 0.51[/tex]
Thus, option c is correct.
A similar problem is given at https://brainly.com/question/24174994
who goes to Catonsville middle school pls answer
Answer:
Uh not me but I don't think you should leak your schools name...
in a class there are 48 students the number of the girls is 3 times how many boys and girls are in class
Answer:
There are 12 boys and 36 girls.
Step-by-step explanation:
This equation should help explain it.
x + 3x = 48
Let's say that there are an x number of boys. Then there would be 3 times x of girls. So x (the boys) plus 3x (the girls) equal 48 (the total amount of students).
To solve this equation, first add x and 3x to get 4x. Then divide that by 48, and we get x = 2.
The amount of boys = x, so there are 12 boys.
The amount of girls = 3x, so there are 3 times 12, or 36 girls.
what would 2 x (x-3) sum be
Answer:
2x-6 I think
Step-by-step explanation:
What percent of 80 is 112? Please hurry!
Answer:
140
Step-by-step explanation:
Here you go. Hope it helps you
Find x and y. Give reasons to justify your solution. Pleaseee help
Answers:
x = 40 and y = 40
========================================================
Explanation:
The three angles involving x add up to 180 since they form a straight line or straight angle.
3x+0.5x+x = 180
4.5x = 180
x = 180/(4.5)
x = 40
Then note how the 0.5x and 0.5y angles are vertical angle pairs. Vertical angles form when we have two lines cross to form an X shape, and vertical angles are always opposite one another. Also, vertical angles are always the same measure.
0.5x = 0.5y
x = y
40 = y
y = 40
In the second step, I multiplied both sides by 2. Then I plugged in x = 40 we found earlier.
Le regioni italiane bagnate dal mare sono un insieme?
Answer:
non so cosa intendi per intero
Step-by-step explanation:
Può essere più preciso?
PLEASE ANSWER QUICK AND SHOW WORK
Miss Johnson borrow $8,300 to buy a car. She agreed to a
4% interest rate and payments for 5 years.
How much will her interest be?
What is her total debt for buying the car?
Answer:
Interest: $402.20
Total Debt owed: $9,302.00
Step 1: Multiply the principal (the original amount borrowed) by the interest rate (%):
$8,300 x 4% = 360.00 (interest for one year)
Step 2: Find out how many years she will be paying back the loan and add that number of years to the first payment year ($360). ($360 + 5years = 365 total payments) Then multiply the total number of payments by the interest rate ($365 x .04 = $14.60 interest per payment).
Step 3: Add up all the yearly interests ($14.60 per payment x 12 months = $181.20 yearly interest)
Step 4: Add the yearly interest to the total debt owed.
$9,302 + $181.20 = $9,483.20 total debt
Total amount owing after 5 years = $8,300+($365 x .04 interest rate per payment for 60 months)=10,605.00 dollars owed in 5 years of payments. Interest owed is 10,605 x .04=$410.20 for a grand total of 10,915.20 dollars owed overall for this 4% loan which was paid back over a period of five years with twelve monthly payments per year at four percent interest rate per month ($410.20/12=$34.02).
how far does the object go
2 hours at 75km\h
Answer:
150 miles per hourStep-by-step explanation:
Objective: finding the distance
Formula: speed × time = distance
75 × 2 = 150
final answer: 150 mph
1. John is going to join a gym. He must pay a one-time membership fee of $75 and a monthly fee of $30. Let m = the number of months John has his membership. Write an expression to represent this situation How much will John pay for 6 months of membership?
2. Madison is having a party. She went to the store and bought a cake for $18.50 and 20 balloons. Her total bill was $63.50. How much did each balloon cost if they all cost the same? Write and solve an equation. Please look over these again. Webmail your answers to get your points back.
John's membership in the gym and Madison's party are illustrations of linear equations.
1. John's equation
The given parameters are:
[tex]\mathbf{Base = 75}[/tex]
[tex]\mathbf{Monthly = 30}[/tex]
The monthly expression is:
[tex]\mathbf{f(m) = Base + Monthly \times m}[/tex]
So, we have:
[tex]\mathbf{f(m) = 75+ 30 \times m}[/tex]
[tex]\mathbf{f(m) = 75+ 30m}[/tex]
For 6 months, we have:
[tex]\mathbf{f(6) = 75+ 30 \times 6}[/tex]
[tex]\mathbf{f(6) = 255}[/tex]
Hence, the expression that represents the situation is [tex]\mathbf{f(m) = 75+ 30m}[/tex], and the amount for 6 months of membership is $255
2. Madison's party
The given parameters are:
[tex]\mathbf{Cake = 18.50}[/tex]
[tex]\mathbf{Balloon = 20}[/tex]
[tex]\mathbf{Total = 63.50}[/tex]
Let n represent the cost of each balloon.
So, the equation is:
[tex]\mathbf{Cake + Balloon \times n = Total}[/tex]
This gives:
[tex]\mathbf{18.50 + 20 \times n = 63.50}[/tex]
Subtract 18.50 from both sides
[tex]\mathbf{ 20 \times n = 45}[/tex]
Divide both sides by 20
[tex]\mathbf{ n = 2.25}[/tex]
Hence, the expression that represents the situation is [tex]\mathbf{18.50 + 20 \times n = 63.50}[/tex], and the cost of each balloon is $2.25
Read more about linear equations at:
https://brainly.com/question/11897796