Answer:
[tex]10[/tex].
Step-by-step explanation:
See below for a proof of why all but the first digit of this [tex]N[/tex] must be "[tex]9[/tex]".
Taking that lemma as a fact, assume that there are [tex]x[/tex] digits in [tex]N[/tex] after the first digit, [tex]\text{A}[/tex]:
[tex]N = \overline{\text{A} \, \underbrace{9 \cdots 9}_{\text{$x$ digits}}}[/tex], where [tex]x[/tex] is a positive integer.
Sum of these digits:
[tex]\text{A} + 9\, x= 2021[/tex].
Since [tex]\text{A}[/tex] is a digit, it must be an integer between [tex]0[/tex] and [tex]9[/tex]. The only possible value that would ensure [tex]\text{A} + 9\, x= 2021[/tex] is [tex]\text{A} = 5[/tex] and [tex]x = 224[/tex].
Therefore:
[tex]N = \overline{5 \, \underbrace{9 \cdots 9}_{\text{$224$ digits}}}[/tex].
[tex]N + 1 = \overline{6 \, \underbrace{000 \cdots 000000}_{\text{$224$ digits}}}[/tex].
[tex]N + 2021 = 2020 + (N + 1) = \overline{6 \, \underbrace{000 \cdots 002020}_{\text{$224$ digits}}}[/tex].
Hence, the sum of the digits of [tex](N + 2021)[/tex] would be [tex]6 + 2 + 2 = 10[/tex].
Lemma: all digits of this [tex]N[/tex] other than the first digit must be "[tex]9[/tex]".
Proof:
The question assumes that [tex]N\![/tex] is the smallest positive integer whose sum of digits is [tex]2021[/tex]. Assume by contradiction that the claim is not true, such that at least one of the non-leading digits of [tex]N[/tex] is not "[tex]9[/tex]".
For example: [tex]N = \overline{(\text{A})\cdots (\text{P})(\text{B}) \cdots (\text{C})}[/tex], where [tex]\text{A}[/tex], [tex]\text{P}[/tex], [tex]\text{B}[/tex], and [tex]\text{C}[/tex] are digits. (It is easy to show that [tex]N[/tex] contains at least [tex]5[/tex] digits.) Assume that [tex]\text{B} \![/tex] is one of the non-leading non-"[tex]9[/tex]" digits.
Either of the following must be true:
[tex]\text{P}[/tex], the digit in front of [tex]\text{B}[/tex] is a "[tex]0[/tex]", or[tex]\text{P}[/tex], the digit in front of [tex]\text{B}[/tex] is not a "[tex]0[/tex]".If [tex]\text{P}[/tex], the digit in front of [tex]\text{B}[/tex], is a "[tex]0[/tex]", then let [tex]N^{\prime}[/tex] be [tex]N[/tex] with that "[tex]0\![/tex]" digit deleted: [tex]N^{\prime} :=\overline{(\text{A})\cdots (\text{B}) \cdots (\text{C})}[/tex].
The digits of [tex]N^{\prime}[/tex] would still add up to [tex]2021[/tex]:
[tex]\begin{aligned}& \text{A} + \cdots + \text{B} + \cdots + \text{C} \\ &= \text{A} + \cdots + 0 + \text{B} + \cdots + \text{C} \\ &= \text{A} + \cdots + \text{P} + \text{B} + \cdots + \text{C} \\ &= 2021\end{aligned}[/tex].
However, with one fewer digit, [tex]N^{\prime} < N[/tex]. This observation would contradict the assumption that [tex]N\![/tex] is the smallest positive integer whose digits add up to [tex]2021\![/tex].
On the other hand, if [tex]\text{P}[/tex], the digit in front of [tex]\text{B}[/tex], is not "[tex]0[/tex]", then [tex](\text{P} - 1)[/tex] would still be a digit.
Since [tex]\text{B}[/tex] is not the digit [tex]9[/tex], [tex](\text{B} + 1)[/tex] would also be a digit.
let [tex]N^{\prime}[/tex] be [tex]N[/tex] with digit [tex]\text{P}[/tex] replaced with [tex](\text{P} - 1)[/tex], and [tex]\text{B}[/tex] replaced with [tex](\text{B} + 1)[/tex]: [tex]N^{\prime} :=\overline{(\text{A})\cdots (\text{P}-1) \, (\text{B} + 1) \cdots (\text{C})}[/tex].
The digits of [tex]N^{\prime}[/tex] would still add up to [tex]2021[/tex]:
[tex]\begin{aligned}& \text{A} + \cdots + (\text{P} - 1) + (\text{B} + 1) + \cdots + \text{C} \\ &= \text{A} + \cdots + \text{P} + \text{B} + \cdots + \text{C} \\ &= 2021\end{aligned}[/tex].
However, with a smaller digit in place of [tex]\text{P}[/tex], [tex]N^{\prime} < N[/tex]. This observation would also contradict the assumption that [tex]N\![/tex] is the smallest positive integer whose digits add up to [tex]2021\![/tex].
Either way, there would be a contradiction. Hence, the claim is verified: all digits of this [tex]N[/tex] other than the first digit must be "[tex]9[/tex]".
Therefore, [tex]N[/tex] would be in the form: [tex]N = \overline{\text{A} \, \underbrace{9 \cdots 9}_{\text{many digits}}}[/tex], where [tex]\text{A}[/tex], the leading digit, could also be [tex]9[/tex].
A math teacher claims that the students' test scores are directly proportional to the amount of time spent studying. Amy studies 17 hours for a test and gets a score of 68. At this rate, how many hours would she have to study to get a score of 97?
Answer:
97/4 = 24.25 hours
Step-by-step explanation:
68 = 17x
x = 68/17 = 4
Which graph represents a decreasing trend
Answer:
Excuse me! plz provide the graphs 2.
Using the graph, determine the equation of the axis of symmetry.
Answer:
x = 6
Step-by-step explanation:
The axis of symmetry passes through the vertex of the graph
It is a vertical line with equation
x = c ( c is the x- coordinate of the vertex )
vertex = (6, 1 ) with x- coordinate 6 , then
equation of axis of symmetry is x = 6
PLS HELP ME ON THIS QUESTION I WILL MARK YOU AS BRAINLIEST IF YOU KNOW THE ANSWER PLS GIVE ME A STEP BY STEP EXPLANATION!!
Answer:
It should be c 4,-5
hope it helps
Answer:
c. (4,-5)
Step-by-step explanation:
Point K is currently at (4,5). If reflected about x, the x-coordinate remains 4 and the y-coordinate becomes -5. Giving the answer (4,-5)
the Marked price of a book is rupees 160 if it is sold at 15% discount find the discount amount and selling price
answer is 15%
Step-by-step explanation:
cost prices of book =160
selling prices of book =136
now,rate of discount =loss% (as discount only leads to some kind of loss)
so CP>SP
so loss=CP-SP =160-136=24
loss%= (loss/CP)÷100
=(24/160)÷100
=15%
so rate of discount =15%
Please show your work
[tex]1\frac{2}{3} + 2\frac{3}{4}[/tex]
Answer:
[tex]→1 \frac{2}{3} + 2 \frac{3}{4} \\ = \frac{5}{3} + \frac{11}{4} \\ = \frac{20 + 33}{12} \\ = \frac{53}{12}\\ =\boxed{4\frac{5}{12}}✓[/tex]
53/12 is the right answer.Steps:
1 2/3 + 2 3/4 can also be written as...
5/3 + 11/4
The LCD is 12 so we make both fractions have a denominator of 12.
That gives us 20/12+33/12
Now you can add the numerators (but leave the denominator the same)
That gives us 53/12, but our simplified version would give us 4 5/12 as our final answer.
Answer:
[tex]4\frac{5}{12\\}[/tex]
Please mark brainliest if that helps!
Which angle in ABC has the largest measure?
A.
B.
C.
D. Cannot be determined
Answer:
< B has the largest angle measure.
as it is opposite to longest side of triangle.
Does anyone know the answer plz ?
Answer:The answer is true
Step-by-step explanation:
(I hope this helped you) :)
Help me please. I don't understand geometry.
The dimensions of four rectangles are given below. Which has an area different from the area of each of the other three?
To determine which of the rectangles has a different area, the areas of the four rectangles must be calculated. The rectangle with a different area is rectangle b
The dimension of the 4 rectangles are:
a. length: 4x and width: 4
b. length: 11 and width: x
c. length: 2 and width: 8x
d. length: 16x and width: 1
The area of a rectangle is:
[tex]Area = Length \times Width[/tex]
Rectangle (a)
[tex]Area = 4x \times 4[/tex]
[tex]Area = 16x[/tex]
Rectangle (b)
[tex]Area = 11 \times x[/tex]
[tex]Area = 11x[/tex]
Rectangle (c)
[tex]Area = 2 \times 8x[/tex]
[tex]Area = 16x[/tex]
Rectangle (d)
[tex]Area = 16x \times 1[/tex]
[tex]Area = 16x[/tex]
Rectangles (a), (c) and (d) have the same area (i.e. 16x) while rectangle (b) has 11x as its area.
Hence, the rectangle with a different area is rectangle (b).
Read more about areas of rectangles at:
https://brainly.com/question/14383947
The circumference of a circle is 16πw⁴.
Derive an expression for the area in terms of pi and w
Answer:
A = Pi (8 w**4)**2
Step-by-step explanation:
C = 16 Pi w**4 (given)
C = 2 Pi R (stand forula)
So then find R in terms of w by settting C = C from above
2 Pi r = 16 Pi w**4
2R = 16 w**4
R = 8 w**4
SO
A = Pi R**2
A = Pi (8 w**4)**2
Find C to two decimal places and find the measurement of angle be use your calculator
Let's solve
P=8B=5Using Pythagorean theorem
[tex]\\ \sf\longmapsto H^2=P^2+B^2[/tex]
[tex]\\ \sf\longmapsto c^2=8^2+5^2[/tex]
[tex]\\ \sf\longmapsto c^2=64+25[/tex]
[tex]\\ \sf\longmapsto c^2=89[/tex]
[tex]\\ \sf\longmapsto c=\sqrt{89}[/tex]
[tex]\\ \sf\longmapsto c\approx 9.22[/tex]
If the circumference of a right cylinder is tripled, the volume will increase by a factor of _____.
Answer:the answer is 9
Step-by-step explanation:
Find the equivalent exponential expression.
(4^2)4
Answer:
4^8
Step-by-step explanation:
If the second 4 is an exponent, as in (4^2)^4, then multiply the exponents.
(4^2)^4 = 4^(2 * 4) = 4^8
14. Peter needs to buy a package of pencils to write his final exam. The store offers two packages.
Package 1: pack of 6 pencils for $1.68
Package 2: pack of 9 pencils for $2.34
Determine the cost per pencil. Which is the better deal? Round to 2 decimal places. Show all your work for full marks. (3 marks)
simplify (4+√3)(4-√3)
Answer:
13
Step-by-step explanation:
(4+√3)(4-√3) = (4)^2-(√3)^2 =16-3 = 13
Answer:
Step-by-step explanation:
(a + b)(a -b) =a² - b²
a = 4 and b = √3
(4 + √3)(4 - √3)= 4² - (√3)²
= 16 - √3*√3
= 16 - 3
= 13
Jenn starts out with $2000 in her bank account. On average, she spends $150 a week from her account. At that rate, how many weeks will it take her to run out of money?
Answer:
About 13 weeks
Step-by-step explanation:
3x - 2y = 16 and x - 2y = 4 (any method <3)
Answer: (x, y) = (6, 1)
This means x = 6 and y = 1
==========================================================
Explanation:
I'll use the substitution method to solve this system.
Let's solve the second equation for x
x-2y = 4
x = 4+2y
Then plug that into the first equation so we can solve for y.
3x - 2y = 16
3(4+2y) - 2y = 16 ... x replaced with 4+2y
12+6y - 2y = 16
12 + 4y = 16
4y = 16-12
4y = 4
y = 4/4
y = 1
Lastly, use this y value to find x
x = 4 + 2y
x = 4 + 2(1)
x = 6
The solution as an ordered pair is (x, y) = (6, 1)
---------------------------------
Checking the answer:
Plug those x,y coordinates into the first equation
3x - 2y = 16
3(6) - 2(1) = 16
18 - 2 = 16
16 = 16
That confirms the first equation. Repeat for the second equation
x - 2y = 4
6 - 2(1) = 4
6 - 2 = 4
4 = 4
Both equations are confirmed.
please answer this!!!
Answer:
C 20
Step-by-step explanation:
use sine law
Answer:
C, 20
Step-by-step explanation:
Angle c= 30
side AC= 40
sin(30)=x/40
40sin(30)=x
x=20
A bag contains eight tiles labeled A, B, C, D, E, F, G, and H. One tile will be randomly picked.
What is the probability of picking a vowel?
Write your answer as a fraction.
Answer:
1/4
Step-by-step explanation:
Count all of the vowels (this will be your numerator):
A and E
2
Count all of the letters (this will be your denominator):
A, B, C, D, E, F, G, and H
8
Write this as a fraction:
2/8
Simplify:
2/8 = 1/4
HELP ME PLS I NEEDA GET THIS RIGHT PLS PLS ITS PYTHAGOREAN THEOREM
2.8 mm
2mm^2=4mm
4mm+4mm = 8mm
square root of 8mm is 2sqrt2
2sqrt 2 is 2.8 mm
Solve A = 1/2bh for h
Answer:
2A /b = h
Step-by-step explanation:
A = 1/2 bh
Multiply each side by 2
2A = 2*1/2 bh
2A = bh
Divide each side by b
2A/b = bh/b
2A /b = h
HELPPP
Which shapes have the greatest area?
(Select all that apply.)
Answer is 1st and 3rd shape
Whose area is 4 units
Answered by Gauthmath must click thanks and mark brainliest
It is Keke’s birthday, and her parents want to surprise her with a room full of balloons. Use the Fermi process
to estimate the number of balloons needed to fill Keke’s living room. Assume the living room is a rectangular
prism with a length of 30 feet, a width of 45 feet, and a height of 11 feet. Assume the balloons are spheres
with a radius of 0.45 feet. Show your work
Answer:
im not sure sorry .
Step-by-step explanation:
The data below are the test scores of the students in a math class.
97, 76, 84, 82, 90, 95, 77, 79, 80, 82, 84, 77, 100, 78, 87
Create a stem-and-leaf plot to represent the data.
how???
First, we can order the set in ascending order to get
76,77, 77, 78,79, 82, 82 ,84, 84, 87, 90, 95, 97, 100.
A stem-and-leaf plot has the tens digits on the left side, and the units digits on the right side, so this set would look like
7 | 6, 7, 7, 8, 9
8 | 2, 2, 4, 4, 7
9 | 0, 5, 7
10 | 0
calculate the speed, in ms-¹ of vehicle A and of vehicle B
9514 1404 393
Answer:
A: 0.32 m/sB: 0.56 m/sStep-by-step explanation:
The speed is the ratio of the change in distance to the corresponding change in time.
Vehicle A moves from a position of 12 m to one of 28 m in 50 seconds, so its speed is ...
A = (28 -12)/50 m/s = 16/50 m/s = 0.32 m/s
Vehicle B moves from 0 to 28 m in 50 seconds, so its speed is ...
B = (28 m)/(50 s) = 0.56 m/s
a horizontally laid standard weight pipe has a diameter of 10 inches and is 12 feet long. The pipe is filled 9 inches high with water. How many gallons of water does the pipe hold? (Round your answer to the nearest gallon.) Please help.
Answer:
d isósceles hijo muy graciosa ya no me acuerdo de nada y tu q ases hablas con el
Is 8.888... a rational number?
=================================================
Explanation:
Since the decimal repeats itself infinitely (the 8s go on forever), this is one sign that we have a rational number.
Rational numbers always have some kind of infinitely repeating pattern when we convert them to decimal form.
---------------------
Extra info (optional section)
If you want to determine what this number is equal to, then let's say that
x = 8.8888...
Multiplying both sides by 10 gets us
10x = 88.888....
Now we'll subtract the two equations
The 10x-x becomes 9x while the 88.8888...-8.8888... turns into 80
We're left with 9x = 80 which solves to x = 80/9
Therefore, 80/9 = 8.8888.... showing that we have a rational number
Any rational number is basically a fraction of two whole numbers.
Which of the following are valid probability distributions?
Answer:
Step-by-step explanation:
HELP PLEASE!!
Which best describes the relationship between the lines
with equations -3x – 4y = 1 and -6x – 8y = 2?
A. Perpendicular
B. Neither perpendicular or parallel
C. Parallel
D. Same line
Answer:
same line
Step-by-step explanation:
its the exact same equation, but the second is multiplied by 2
