x2 – 3x – 28 = (x-7)(x+4)
Answer:
On the top:-28
On the bottom: -3
On the sides: -7 and 4
X2-3x-28=(x-7)(x+4)
Step-by-step explanation: I got it correct on Edge
-3 = 7 - BLANK pls tell me what blank is
Answer:
10
Step-by-step explanation:
-3 = 7 - x
Add x to both sides
x -3 = 7 - x +x
x - 3 = 7
Now, add 3 to both sides
x - 3 + 3 = 7 + 3
x = 10
Answer:
[tex]\boxed{10}[/tex]
Step-by-step explanation:
[tex]-3=7- \sf BLANK[/tex]
[tex]\sf Subtract \ 7 \ from \ sides.[/tex]
[tex]-3-7=-7+7- \sf BLANK[/tex]
[tex]-10=- \sf BLANK[/tex]
[tex]\sf Multiply \ both \ sides \ by \ -1.[/tex]
[tex]-10(-1)=(-1)- \sf BLANK[/tex]
[tex]10= \sf BLANK[/tex]
Al’s Produce Stand sells 6 ears of corn for $1.50. Barbara’s Produce Stand sells 13 ears of corn for $3.12. Write two equations, one for each produce stand, that model the relationship between the number of ears of corn sold and the cost.
Answer:
6n = 1.50
and
13n = 3.12
Step-by-step explanation:
Here in this question, we are interested in writing equations that relate the number of ears of corn sold and the cost.
For Al’s produce stand, let the price per corn sold be n
Thus;
6 * n = 1.50
6n = $1.50 •••••••(i)
For the second;
let the price per corn sold be n;
13 * n = $3.12
-> 13n = 3.12 •••••••••(ii)
1. Why is f(x)=(3x+13)2+89 not the vertex form of f(x)=9x2+2x+1? 2. What is the vertex of the parabola with the equation y=(x−2)2+10?
Answer:
Step-by-step explanation: u hv 2 make a table for x and y and put in #'s like 1,2,3,4 so u get 1 side of the parabola. x-1, y-11/x-2,y-11/x-3,y-11/x-4,y-14; here u c that u have 2 y's=11 so the points between are the Vertex Points of (2,10)
X has a coefficient, the vertext is (2,10)
Is △FHK similar to △GHJ? If so, which postulate or theorem proves these two triangles are similar? △FHK is similar to △GHJ by the SSS Similarity Theorem. △FHK is similar to △GHJ by the SSA Similarity Theorem. △FHK is similar to △GHJ by the SAS Similarity Theorem. △FHK is not similar to △GHJ.
Answer:
ΔFHK and ΔGHJ are the similar triangles by SAS similarity theorem.
Step-by-step explanation:
Picture for the given question is missing; find the picture attached.
If [tex]\frac{\text{FH}}{\text{GH}}=\frac{\text{HK}}{\text{HJ}}[/tex] and ∠H ≅ ∠H
Then ΔFHK ~ ΔGHJ
[tex]\frac{\text{FH}}{\text{GH}}=\frac{\text{HK}}{\text{HJ}}[/tex]
[tex]\frac{(12+10)}{10}=\frac{(15+18)}{15}[/tex]
[tex]\frac{22}{10}=\frac{33}{15}[/tex]
[tex]\frac{11}{5}=\frac{11}{5}[/tex]
Since, [tex]\frac{\text{FH}}{\text{GH}}=\frac{\text{HK}}{\text{HJ}}[/tex] and ∠H ≅ ∠H [By reflexive property]
Therefore, ΔFHK and ΔGHJ are the similar triangles by SAS similarity theorem.
Option (3) will be the answer.
Answer:
ΔFHK and ΔGHJ are similar triangles by the SAS similarity theorem.
Step-by-step explanation:
Verified correct with test results.
pls i want help in this sum
Step-by-step explanation: The first rectangle to the right is 24 because 10+14 equals 24. The rectangle to the left is 19 because 10+9 equals 19. Finally the rectangle on the bottom is 23 because 14+9 is 23
A mother who is 35 years old has two sons, one of whom is twice as old as the other. In 3 years the sum of all their ages will be 59 years. How old are the boys at present ?
Answer:
son2: 5
son1: 10
Step-by-step explanation:
2x (son1) + x (son2) + 35 (mother) + 3 (years)*3 (people) = 59
3x = 15
x = 5
The age of each boy at present will be 2 years and 3 years.
What is the linear system?A linear system is one in which the parameter in the equation has a degree of one. It might have one, two, or even more variables.
Let the age of the sons will be x and y.
A mother who is 35 years old has two sons, one of whom is twice as old as the other. Then the equation will be
x = 2y
In 3 years, the sum of all their ages will be 59 years. Then the equation will be
x + y + x + 1 + y + 1 + x + 2 + y + 2 + 35 = 59
Simplify the equation, we have
3x + 3y + 41 = 59
6y + 3y = 59 – 41
9y = 18
y = 2
Then the value of x will be
x = 2y
x = 2(2)
x = 4
Thus, the age of each boy at present will be 2 years and 3 years.
More about the linear system link is given below.
https://brainly.com/question/20379472
#SPJ2
Hi how to solve this pythagoras theorem
Answer:
The perimeter of the triangle is 40.
Step-by-step explanation:
Pythagorean Theorem: If x and y are the leg lengths of a right triangle, then r = √(x^2 + y^2) is the length of the hypotenuse. Alternatively, x^2 + y^2 = r^2.
The side lengths 2x, 4x - 1 and 4x + 1 are already arranged in ascending order. Thus, (2x^)2 + (4x - 1)^2 = (4x + 1).
Performing the indicated operations, we get:
4x^2 + 16x^2 - 8x + 1 = 16x^2 + 8x + 1. Simplify this first by combining like terms:
20x^2 - 16x = 16x^2, or
4x^2 - 16x = 0, or
4x(x - 4) = 0. Thus, x = 0 (which makes no sense here) or x = 4.
The perimeter of the rectangle is the sum of the three sides 2x, 4x - 1 and 4x + 1. Substituting 4 for x, we get
P = 8 + 16 - 1 + 16 + 1, or 40.
The perimeter of the triangle is 40.
In politics, marketing, etc. We often want to estimate a percentage or proportion p. One calculation in statistical polling is the margin of error - the largest (reasonble) error that the poll could have. For example, a poll result of 72% with a margin of error of 4% indicates that p is most likely to be between 68% and 76% (72% minus 4% to 72% plus 4%). In a (made-up) poll, the proportion of people who like dark chocolate more than milk chocolate was 32% with a margin of error of 2.2%. Describe the conclusion about p using an absolute value inequality.
Answer: |p-72% |≤ 4%
Step-by-step explanation:
Let p be the population proportion.
The absolute inequality about p using an absolute value inequality.:
[tex]|p-\hat{p}| \leq E[/tex] , where E = margin of error, [tex]\hat{p}[/tex] = sample proportion
Given: A poll result of 72% with a margin of error of 4% indicates that p is most likely to be between 68% and 76% .
|p-72% |≤ 4%
⇒ 72% - 4% ≤ p ≤ 72% +4%
⇒ 68% ≤ p ≤ 76%.
i.e. p is most likely to be between 68% and 76% (.
The conclusion about p using an absolute value inequality is in the range of 29.8% to 34.2%.
What is absolute value inequality?An expression using absolute functions and inequality signs is known as an absolute value inequality.
We know that the absolute value inequality about p using an absolute value inequality is written as,
[tex]|p-\hat p| \leq E[/tex]
where E is the margin of error and [tex]\hat p[/tex] is the sample proportion.
Now, it is given that the poll result of 72% with a margin of error of 4% indicates that p is most likely to be between 68% and 76%. Therefore, p can be written as,
[tex]|p-0.72|\leq 0.04\\\\(0.72-0.04)\leq p \leq (0.72+0.04)\\\\0.68 \leq p\leq 0.76[/tex]
Thus, the p is most likely to be between the range of 68% to 76%.
Similarly, the proportion of people who like dark chocolate more than milk chocolate was 32% with a margin of error of 2.2%. Therefore, p can be written as,
[tex]|p-\hat p|\leq E\\\\|p-0.32|\leq 0.022\\\\(0.32-0.022)\leq p \leq (0.32+0.022)\\\\0.298\leq p\leq 0.342[/tex]
Thus, the p is most likely to be between the range of 29.8% to 34.2%.
Hence, the conclusion about p using an absolute value inequality is in the range of 29.8% to 34.2%.
Learn more about Absolute Value Inequality:
https://brainly.com/question/4688732
April typed a 5 page report in 50 mintues. Each page had 500 words at what rate is April typing
Answer:
Amy types at a rate of 50 words per minute
Step-by-step explanation:
In this question, we are interested in calculating the rate at which April is typing.
From the question, we can deduce that she typed a 5 page report, with each page having a total of 500 words.
Now, if each page has 500 words, the total number of words in all of the pages will be 5 * 500 = 2,500 words
Now, from here, we can see that 2,500 words were typed in 50 minutes.
The number of words per minute will be ;
Total number of words/Time taken = 2500 words/50 minutes
That will give a value of 50 words per minute
Find the coefficient of third term of (2x−1)^6.
240
using pascals trianle
for the power 6 it is
1, 6,15,20, 15,6, 1
and for the third term (2x)^4 and (-1)^2
[tex]15 \times {(2x)}^{4} \times {( - 1)}^{2} [/tex]
[tex]240 {x}^{4} [/tex]
Since only the coefficient is needed
the answer is 240.
The required coefficient of third term is 480.
Coefficient of the third term of (2x−1)^6 to be determine.
Coefficient is defined as the integer present adjacent to the variable.
Here, (2x−1)^6
Using binomial expansion,
Third term = P(6,2)(2x)^6-2(-1)^2
= 6*5*16x^4
= 480x^4
Thus, the required coefficient of third term is 480.
Learn more about coefficient here:
https://brainly.com/question/2507029
#SPJ2
20 PTS PLEASE HELP!!!!
Select the correct answer from each drop-down menu.
The function below describes the number of students who enrolled at a university, where f(t) represents the number of students and t represents the time in years.
Initially, (1.03, 3, 19,055, 18,500) students enroll at the university. Every,(1years, t years, 2years, 3years) the number of students who enroll at the university increases by a factor of (1.03, 3, 19,055, 18,500).
Answer:
Initially 18,500 students
Every 1 year
increase by a factor 1.03
Step-by-step explanation:
The missing information is selected from the given options from the drop down menu. The correct answers are : Initially 18,500 students enroll at the university. Every 1 years the number of students who enroll at the university increases by a factor 1.03.
F(t) = 18,500 * (1.03)^t
The drama club is selling tickets to its play. An adult ticket costs $15 and a student ticket costs $11. The auditorium will seat 300 ticket-holders. The drama club wants to collect at least $3630 from ticket sales.
Answer:
83 adult tickets and 217 student tickets.
Step-by-step explanation:
Let number of adult tickets sold = [tex]x[/tex]
Given that total number of tickets = 300
So, number of student tickets = 300 - [tex]x[/tex]
Cost of adult ticket = $15
Cost of student ticket = $11
Total collection from adult tickets = $[tex]15x[/tex]
Total collection from student tickets = [tex](300-x)\times 11 = 3300-11x[/tex]
Given that overall collection = $3630
[tex]15x+(3300-11x) = 3630\\\Rightarrow 15x-11x=3630-3300\\\Rightarrow 4x = 330\\\Rightarrow x = 82.5[/tex]
So, for atleast $3630 collection, there should be 83 adult tickets and (300-83 = 217 student tickets.
Now , collection = $3632
Can someone please help! Thx
Answer:
Hey there!
The angle is 24 degrees.
The angle complementary to the 66 degrees is 24 degrees, and the unknown angle is also 24 degrees because these are alternate interior angles.
Let me know if this helps :)
A shell of mass 8.0-kg leaves the muzzle of a cannon with a horizontal velocity of 600 m/s. Find the recoil velocity of the cannon, if its mass is 500kg.
Answer:
velocity of recoil velocity of cannon is -9.6 m/sec
Step-by-step explanation:
according to law of conservation of momentum
total momentum of isolated system of body remains constant.
momentum = mass of body* velocity of body.
__________________________________
in the problem the system is
shell + cannon
momentum of shell = 8*600 = 4800 Kg-m/sec
let the velocity of cannon be x m/sec
momentum of cannon = 500*x = 500x Kg-m/sec
initially the system of body is in rest (before the shell is fired) hence, total momentum of the system i is 0
applying conservation of momentum
total momentum before shell fired = total momentum after the shell is fired
0 = momentum of shell + momentum of cannon
4800 + 500x = 0
x = -4800/500 = -9.6
Thus, velocity of recoil velocity of cannon is -9.6 m/sec
here negative sign implies that direction of velocity of cannon is opposite to that of velocity of shell.
Find the product of 0.3×0.23
Answer:
0.069
Step-by-step explanation:
0.3*0.23=0.069
Can anyone tell me the answer of the question attached below??
Answer: AE = 5
Step-by-step explanation:
I sketched the triangle based on the information provided.
since ∠A = 90° and is divided into three equal angles, then ∠BAD, ∠DAE, and ∠CAE = 30°
Since AB = 5 and BC = 10, then ΔCAB is a 30°-60°-90° triangle which implies that ∠B = 60° and ∠C = 30°
Using the Triangle Sum Theorem, we can conclude that ∠ADB = 90°, ∠ADE = 90°, ∠ AED = 60°, AND ∠ AEC = 120°
We can see that ΔAEC is an isosceles triangle. Draw a perpendicular to divide it into two congruent right triangles. Label the intersection as Z. ΔAEZ and ΔCEZ are 30°-60°-90° triangles.
Using the 30°-60°-90° rules for ΔABC we can calculate that AC = 5√3.
Since we divided ΔAEC into two congruent triangles, then AZ = [tex]\dfrac{5\sqrt 3}{2}[/tex]
Now use the 30°-60°-90° rules to calculate AE = 5
Set A={XIX is an even whole number between 0 and 2) = 0
True? or false?
false
Step-by-step explanation:
false
SIMPLIFY.
(5c^2 + c) - (3c^2 + 11c)
Answer:2 c^2 - 10c
Step-by-step explanation:
A timeline. 27 B C E to 180 C E PAX ROMANA. 44 B C E The Roman Empire was founded. 80 C E The Colosseum was built. 121 C E Hadrian's Wall was built in England to keep out enemies. 306 C E Constantine became emperor.
How many years passed between the building of the Colosseum and the building of Hadrian’s Wall?
201
121
41
36
Answer:
the answer is 41
Step-by-step explanation:
C. 41
Step-by-step explanation:
if your ans is correct i will choose you as a brainlist when the number of student of a school was increased by 30% it became 455. Find the previous number student.
Step-by-step explanation:
find 30% of 455
which is = 136.5
then subtract 136.5 from the original number(455)
455 - 136.5
=318.5 student
what are the possible polynomial expression for dimensions of the cuboid whose volume is 12y2 + 8y -20
!
!
!
!
!
plz answer fast
Answer:
The answer is below
Step-by-step explanation:
The volume of a cuboid is the product of its length, height and breadth. It is given by:
Volume = length × breadth × height
Since the volume is given by the expression 12y² + 8y - 20. That is:
Volume = 12y² + 8y - 20 = 4(3y² + 2y - 5) = 4(3y² + 5y - 3y -5) = 4[y(3y + 5) -1(3y + 5)]
Volume = 4(y-1)(3y+5)
Or
Volume = 12y² + 8y - 20 = 2(6y² +4y - 10) = 2(6y² + 10y - 6y -10) = 2[y(6y + 10) -1(6y + 10)]
Volume = 2(y-1)(6y+10)
Therefore the dimensions of the cuboid are either 4, y-1 and 3y+5 or 2, y-1 and 6y+10
Answer:
plz mark me as brainiest
What is the best way to display data if there is a wide range and we want to see individual data?
a.frequency table with intervals
b.stem-and-leaf plot
c.line plot
d.frequency table
Answer:
The correct option is;
b. Stem and leaf plot
Step-by-step explanation:
A stem-and-leaf plot shows the data shape and the densities of the different classes in a graphical form such that the information in the data such as the data characteristics are self displayed by the data numbers arranged in the stem-and-leaf plot. The stem-and-leaf plot keeps the raw numerical data, in the form they were obtained and by their arrangement, outliers are easily spotted.
Answer: b. stem-and-leaf plot
Step-by-step explanation:
hope this helps
If we did not write the equation 5x=21, instead we wrote it 21=5x,
we would get a different solution.
O True
O False
Answer:
Step-by-step explanation:
5x = 21 and 21 = 5x are identical relationships, and so the solution would be the same in both cases. (Commutative Property: order of addition/subtraction is immaterial)
Solve this problem... Really urgent
Answer:
[tex] \boxed{\sf Time \ taken = 15 \ minutes} [/tex]
Given:
Initial speed (u) = 65 km/h
Final speed (v) = 85 km/h
Acceleration (a) = 80 km/h²
To Find:
Time taken for car to achieve a speed of 85 km/h in minutes
Step-by-step explanation:
[tex]\sf From \ equation \ of \ motion:[/tex]
[tex] \boxed{ \bold{v = u + at}}[/tex]
By substituting value of v, u & a we get:
[tex] \sf \implies 85 = 65 + 80t[/tex]
Substract 65 from both sides:
[tex] \sf \implies 85 - 65 = 65 - 65 + 80t[/tex]
[tex] \sf \implies 20 = 80t[/tex]
[tex] \sf \implies 80t = 20[/tex]
Dividing both sides by 80:
[tex] \sf \implies \frac{ \cancel{80}t}{ \cancel{80}} = \frac{20}{80} [/tex]
[tex] \sf \implies t = \frac{2 \cancel{0}}{8 \cancel{0}} [/tex]
[tex] \sf \implies t = \frac{ \cancel{2}}{ \cancel{2} \times 4} [/tex]
[tex] \sf \implies t = \frac{1}{4} \: h[/tex]
[tex] \sf \implies t = \frac{1}{4} \times 60 \: minutes[/tex]
[tex] \sf \implies t = 15 \: minutes[/tex]
So,
Time taken for car to achieve a speed of 85 km/h in minutes = 15 minutes
Find the total surface area.
Answer:
143.4 mi²
Step-by-step explanation:
Top: 8x6=48
Bottom: 3x8=24
Sides: 3x8=24 and 24
Trapezoids sides: (6+3)/2*2.6=4.5*2.6=11.7 and 11.7
TOTAL: 48+24+24+24+11.7+11.7= 143.4 mi²
A cube whose edge is 20 cm 1 point
long, has circles on each of its
faces painted black. What is the
total area of the unpainted
surface of the cube if the
circles are of the largest
possible areas?(a) 90.72 cm2 (b)
256.72 cm² (c) 330.3 cm² (d)
514.28 cm?
Answer:
Unpainted surface area = 514.28 cm²
Step-by-step explanation:
Given:
Side of cube = 20 Cm
Radius of circle = 20 / 2 = 10 Cm
Find:
Unpainted surface area
Computation:
Unpainted surface area = Surface area of cube - 6(Area of circle)
Unpainted surface area = 6a² - 6[πr²]
Unpainted surface area = 6[a² - πr²]
Unpainted surface area = 6[20² - π10²]
Unpainted surface area = 6[400 - 314.285714]
Unpainted surface area = 514.28 cm²
Multiply. (2x - 3)(x + 4) a 2x² + 11x - 12 b 2x² + 5x - 12 c 2x² + 11x - 7 d 2x² + 3x - 7
Answer:
2x^2 +5x-12
Step-by-step explanation:
(2x - 3)(x + 4)
FOIL
first 2x*x = 2x^2
outer 2x*4 = 8x
inner -3x
last -3*4 = -12
Add these together
2x^2 +8x-3x-12
Combine like terms
2x^2 +5x-12
Drag each tile to the correct box.
Answer:
The order is 4) → 5) → 6) → 7) → 2) → 1) → 3)
Please find diagram with the arrangements
Step-by-step explanation:
The horizontal width of an hyperbola
For
1) [tex]\dfrac{(y - 11)^2}{7^2} -\dfrac{(x - 2)^2}{6^2} = 1[/tex]
h = 2, k = 11
The widths are;
Horizontal (h - a, k) to (h + a, k) which is (2 - 7, 11) to (2 + 7, 11) = 14 units wide
(h, k - b) to (h, k + b) which is (2, 11 -6) to (2, 11 + 6) = 12 units wide
2)
[tex]\dfrac{(y - 1)^2}{5^2} -\dfrac{(x - 7)^2}{12^2} = 1[/tex]
h = 7, k = 1
(h - a, k) to (h + a, k) which is (7 - 5, 1) to (7 + 5, 1) = Horizontal width 10 units wide
(h, k - b) to (h, k + b) which is (7, 1 -12) to (7, 1 + 12) = 24 units wide
3) [tex]\dfrac{(x - 6)^2}{6^2} -\dfrac{(y + 1)^2}{3^2} = 1[/tex]
h = 6, k = -1
a = 8, b = 3
The widths are;
(6 - 8, -1) to (6 + 8, -1) Horizontal width = 16
(6, -1 - 3) to 6, -1 + 3) width = 6
4) [tex]\dfrac{(x - 4)^2}{2^2} -\dfrac{(y + 2)^2}{5^2} = 1[/tex]
h = 4, k = -2, a = 2, b = 5
(4 - 2, (-2)) to (4 + 2, (-2)) Horizontal width = 4
(4, -2 - 5) to (4, -2 + 5) width = 10
5) [tex]\dfrac{(y + 5)^2}{2^2} -\dfrac{(x + 4)^2}{3^2} = 1[/tex]
h = -4, k = -5, a = 2, b = 3
(-4 - 2, (-5)) to (-4 + 2, (-5)) Horizontal width = 4
(-4, -5 - 3) to (4, -5 + 3) width = 6
6) [tex]\dfrac{(y + 1)^2}{2^2} -\dfrac{(x - 1)^2}{9^2} = 1[/tex]
h = 1, k = -1, a = 2, b = 9
(1 - 2, (-1)) to (1 + 2, (-1)) Horizontal width = 4
(1, -1 - 9) to (1, -1 + 9) width = 18
7) [tex]\dfrac{(x + 7)^2}{4^2} -\dfrac{(y - 9)^2}{9^2} = 1[/tex]
h = -7, k = 9, a = 4, b = 9
(-7 - 4, 9) to (-7 + 4, 9) Horizontal width = 8
(-7, 9 -9) to (-7, 9 + 9) width = 18
G(x)= -\dfrac{x^2}{4} + 7g(x)=− 4 x 2 +7g, left parenthesis, x, right parenthesis, equals, minus, start fraction, x, squared, divided by, 4, end fraction, plus, 7 What is the average rate of change of ggg over the interval [-2,4][−2,4]open bracket, minus, 2, comma, 4, close bracket?
Answer:
-1/2Step-by-step explanation:
Given the function [tex]G(x)= -\dfrac{x^2}{4} + 7[/tex], the average rate of change of g(x) over the interval [-2,4], is expressed as shown below;
Rate of change of the function is expressed as g(b)-g(a)/b-a
where a - -2 and b = 4
[tex]G(4)= -\dfrac{4^2}{4} + 7\\G(4)= -\dfrac{16}{4} + 7\\G(4)= -4 + 7\\G(4) = 3\\[/tex]
[tex]G(-2) = -\dfrac{(-2)^2}{4} + 7\\G(-2)= -\dfrac{4}{4} + 7\\G(-2)= -1 + 7\\G(-2)= 6[/tex]
average rate of change of g(x) over the interval [-2,4] will be;
[tex]g'(x) = \frac{g(4)-g(-2)}{4-(-2)}\\ g'(x) = \frac{3-6}{6}\\\\g'(x) = -3/6\\g'(x) = -1/2[/tex]
A cyclist travels at $20$ kilometers per hour when cycling uphill, $24$ kilometers per hour when cycling on flat ground, and $30$ kilometers per hour when cycling downhill. On a sunny day, they cycle the hilly road from Aopslandia to Beast Island before turning around and cycling back to Aopslandia. What was their average speed during the entire round trip?
Answer:
Average speed during the trip = 24 km/h
Step-by-step explanation:
Given:
Speed of cyclist uphill, [tex]v_1[/tex] = 20 km/hr
Speed of cyclist on flat ground = 24 km/h
Speed of cyclist downhill, [tex]v_2[/tex] = 30 km/h
Cyclist has traveled on the hilly road to Beast Island from Aopslandia and then back to Aopslandia.
That means, one side the cyclist went uphill will the speed of 20 km/h and then came downhill with the speed of 30 km/h
To find:
Average speed during the entire trip = ?
Solution:
Let the distance between Beast Island and Aopslandia = D km
Let the time taken to reach Beast Island from Aopslandia = [tex]T_1\ hours[/tex]
Formula for speed is given as:
[tex]Speed = \dfrac{Distance}{Time}[/tex]
[tex]v_1 = 20 = \dfrac{D}{T_1}[/tex]
[tex]\Rightarrow T_1 = \dfrac{D}{20} ..... (1)[/tex]
Let the time taken to reach Aopslandia back from Beast Island = [tex]T_2\ hours[/tex]
Formula for speed is given as:
[tex]Speed = \dfrac{Distance}{Time}[/tex]
[tex]v_2 = 30 = \dfrac{D}{T_2}[/tex]
[tex]\Rightarrow T_2 = \dfrac{D}{30} ..... (2)[/tex]
Formula for average speed is given as:
[tex]\text{Average Speed} = \dfrac{\text{Total Distance}}{\text{Total Time Taken}}[/tex]
Here total distance = D + D = 2D km
Total Time is [tex]T_1+T_2[/tex] hours.
Putting the values in the formula and using equations (1) and (2):
[tex]\text{Average Speed} = \dfrac{2D}{T_1+T_2}}\\\Rightarrow \text{Average Speed} = \dfrac{2D}{\dfrac{D}{20}+\dfrac{D}{30}}}\\\Rightarrow \text{Average Speed} = \dfrac{2D}{\dfrac{30D+20D}{20\times 30}}\\\Rightarrow \text{Average Speed} = \dfrac{2D\times 20 \times 30}{{30D+20D}}\\\Rightarrow \text{Average Speed} = \dfrac{1200}{{50}}\\\Rightarrow \bold{\text{Average Speed} = 24\ km/hr}[/tex]
So, Average speed during the trip = 24 km/h
