1. Bill wants to buy coffee for his class at the LePhooPhoo Coffee Shop. He needs to buy 30 cups of coffee. The large coffees cost $4 and the medium coffees cost $3. If he spends $102 on coffee, how many of each size coffee did he buy?
Answer:
large = 12
medium = 18
Step-by-step explanation:
L + M = 30 => L = 30-M
4L+3M =102
substitute : L with M
=> 4(30-M)+3M =102
120-4M+3M = 102
- M = 102-120
-M = -18
=========> M = 18, L = 12
if {a \index{n}} be an Arithmetic sequence , calculate \frac{1}{a1a2} + \frac{1}{a2a3} +...+ \frac{1}{a39a40}
Given:
[tex]a_n[/tex] is an arithmetic sequence.
To find:
The value of [tex]\dfrac{1}{a_1a_2}+\dfrac{1}{a_2a_3}+...+\dfrac{1}{a_{39}a_{40}}[/tex].
Solution:
We have,
[tex]\dfrac{1}{a_1a_2}+\dfrac{1}{a_2a_3}+...+\dfrac{1}{a_{39}a_{40}}[/tex]
It can be written as:
[tex]=\dfrac{d}{d}\left[\dfrac{1}{a_1a_2}+\dfrac{1}{a_2a_3}+...+\dfrac{1}{a_{39}a_{40}}\right][/tex]
[tex]=\dfrac{1}{d}\left[\dfrac{d}{a_1a_2}+\dfrac{d}{a_2a_3}+...+\dfrac{d}{a_{39}a_{40}}\right][/tex]
[tex]=\dfrac{1}{d}\left[\dfrac{a_2-a_1}{a_1a_2}+\dfrac{a_3-a_2}{a_2a_3}+...+\dfrac{a_{40}-a_{39}}{a_{39}a_{40}}\right][/tex]
[tex]=\dfrac{1}{d}\left[\dfrac{1}{a_1}-\dfrac{1}{a_2}+\dfrac{1}{a_2}-\dfrac{1}{a_3}+....+\dfrac{1}{a_{39}}-\dfrac{1}{a_{40}}\right][/tex]
[tex]=\dfrac{1}{d}\left[\dfrac{1}{a_1}-\dfrac{1}{a_{40}}\right][/tex]
[tex]=\dfrac{1}{d}\left[\dfrac{a_{40}-a_1}{a_1a_{40}}\right][/tex]
[tex]=\dfrac{1}{d}\left[\dfrac{a_1+(40-1)d-a_1}{a_1a_{40}}\right][/tex] [tex][\because a_n=a_1+(n-1)d][/tex]
[tex]=\dfrac{1}{d}\left[\dfrac{39d}{a_1a_{40}}\right][/tex]
[tex]=\dfrac{39}{a_1a_{40}}[/tex]
Therefore, the value of given expression is [tex]\dfrac{39}{a_1a_{40}}[/tex].
Please helpppp I’ll make you the brainiest
Answer: D) f(z) = 7 to the power of 2.
Solve the quadratic by factoring.
x2- 20x + 38= -9x + 8
2. A(an) ______________of a prism is a perpendicular segment that joins the planes of the bases. (The height h is the length of one.)
Answer:
A(an) altitude of a prism is a perpendicular segment that joins the planes of the bases. (The height h is the length of one.)
Step-by-step explanation:
AN ALTITUDE - An altitude of a triangle is a line segment that passes through a vertex and is perpendicular to (i.e. forms a right angle with) the base line (the side opposite the vertex). The expanded base of the altitude is the line that contains the opposing side. The foot of the altitude is the point where the extended base meets the altitude. The area of a triangle can be calculated using altitudes: one half of the product of an altitude's length and its base's length equals the triangle's area. As a result, the longest altitude is perpendicular to the triangle's shortest side. Through trigonometric functions, the heights are also connected to the triangle's sides.
Hence , the answer is an altitude .
At a certain instant the edge of a cube is 7 inches long and the volume is increasing at the rate of 3 cubic inches per minute. How fast is the surface area of the cube increasing
Answer:
The surface area increases at 12/7 square inches per minute
Step-by-step explanation:
Given
[tex]l = 7[/tex] --- side length
[tex]\frac{dV}{dt} = 3in^3/min[/tex] --- Rate at which volume increases
Required
The rate at [tex]which[/tex] the [tex]surface[/tex] area [tex]increases[/tex]
The volume of a cube is:
[tex]V = l^3[/tex]
Differentiate with respect to time
[tex]\frac{dV}{dt} = 3l^2 \cdot \frac{dl}{dt}[/tex]
When [tex]l = 7[/tex] and [tex]\frac{dV}{dt} = 3in^3/min[/tex]
The expression becomes:
[tex]3 = 3 * 7^2 \cdot \frac{dl}{dt}[/tex]
Divide both sides by 3
[tex]1 = 7^2 \cdot \frac{dl}{dt}[/tex]
[tex]1 = 49 \cdot \frac{dl}{dt}[/tex]
Divide both sides by 49
[tex]\frac{dl}{dt} = \frac{1}{49}[/tex]
The surface area is calculated as:
[tex]A= 6l^2[/tex]
Differentiate with respect to time
[tex]\frac{dA}{dt} = 12l\frac{dl}{dt}[/tex]
Substitute: [tex]\frac{dl}{dt} = \frac{1}{49}[/tex] and [tex]l = 7[/tex]
[tex]\frac{dA}{dt} = 12 * 7 *\frac{1}{49}[/tex]
[tex]\frac{dA}{dt} = 12 *\frac{1}{7}[/tex]
[tex]\frac{dA}{dt} = \frac{12}{7}[/tex]
The surface area increases at 12/7 square inches per minute
answer this question for brainilest and points
Answer:
g= 1
Step-by-step explanation:
-3+5+6g=11-3g
-3+5=11-9g
-3-11+5=-9g
-9=-9g
1=g
you want to first isolate the variables on one side. from there you calculate all the real numbers together. then you divide the number being multiplied with teh variable by the number that was calculated on the other side.
Once you have a singluar amount of the variable, you know you have your answer.
Leo wants to determine the average number of texts middle school students send in a day. Since all middle school students are enrolled in history, he randomly surveyed 4 students from each of Mr. Barnes’s eighth-grade history classes. Ms. Lopez and Mrs. Frank also teach eighth-grade history. What should Leo do to ensure his sample is representative of all middle school students?
Answer:
D. He should survey all the students in all the history classes to make sure he collects enough data.
Step-by-step explanation:
correct on edge 2021
Pls anyoneee I need help with this problem
please help me asap i’ll give you a thanks and 10 points
what is the value of x? i need the work for it as well thank you so much!
Answer:
x=19
Step-by-step explanation:
okay so all those angles there are pretty simple. because of the vertical angles theorem, the angles that go across from each other are equal to each other. On a thing like this those intersections are congruent. So knowing this we can assume that (6x+4)=118. so if you solve the basic algebra for that (you can use mathpapa or smt if you really need the work for that) then it comes out as x=19 which you can check.
6x+4=118
subtract 4 from both sides
6x=114
divide by 6 on both sides
x=19
Hope this helps!
i need urgent help with this
Answer:
Problem 1:
Width of the larger version = 2.99 in.
Problem 2:
Friday = 5⅞ miles
Step-by-step explanation:
Problem 1:
Since the cell-phones are similar in shape and the width and length of both are proportional, therefore:
Width of the bigger phone/Width of the smaller phone = length of the bigger phone/length of the smaller phone
Width of smaller phone = 2.6 in.
Length of smaller phone = 5.4 in.
Width of bigger phone = x = ? in.
Length of bigger phone = 6.21 in.
Therefore:
6.21/5.4 = x/2.6
Cross multiply
5.4 × x = 2.6 × 6.21
5.4x = 16.146
Divide both sides by 5.4
x = 16.146/5.4
x = 2.99
Width of the larger version = 2.99 in.
Problem 2:
Jen's goal for the 5 days = 22 miles
The number of miles she ran Mon to Thursday was given.
To meet her goal, let's find the number of miles she has to run to meet her goal.
Thus:
Number of miles to run on Friday = 22 - (4¾ + 5⅛ + 0 + 6¼)
Change to improper fraction
= 22 - (19/4 + 41/8 + 0 + 25/4)
= 22 - ((38 + 41 + 0 + 50)/8)
= 22 - 129/8
= (176 - 129)/8
= 47/8
= 5⅞ miles
Find the height of a cylinder when the surface area is 1004.80 cm squared and the radius is 10 cm.
Step-by-step explanation:
[tex]volume =\pi {r}^{2}h[/tex]
[tex]area = \pi {r}^{2} [/tex]
CALCULATIONremember
[tex]\pi = 22 \div 7[/tex]
So, we will just place the area and equate it to the unknown volume including the height
1004.80 = 22/7 × 10× 10 × h
1004.80 = 314.26h
h = 3.197
What is the area of a triangle shape with a base of 12 feet, sides that are 7 feet, and a height of 9 feet
Answer: The Answer Is 54 ft2
Answer:
54
Step-by-step explanation:
A=1/2(b)(h)
PLEASE HELP, PLEASE....
Answer:
allen= y=3/2+2 billy= y= 3/2+4
Step-by-step explanation:
ok both of the equation are (almost) the same except for the y intercepts.
y=mx+b... you are learning about that hopefully!
so. each of their trees are growing by 3... feet I'll just say feet. that means the slope is three because they are each going up that much. you also have to pay attention to the fact that the year is going up by two, so your tree is actually growing by 1.5 (3 halves) feet each year. now you have to find the y intercept by back tracking. remember that the y intercept is where y is zero and x is whatever it is.
if you go back three on allen, the y intercept is 2 and if you go back on billy, the y intercept is 4.
as for the second question, the lines are parallel. they have the exact same slope so that means that they will never cross because billy's line is higher then allens, billy's tree will always be higher
Fill in the blanks. Then, choose the property of addition you used.
_ + 3 = 3 + 7 is it: associated property, commutative property, or identity property?
0 + _ = 5 is it: associated property, commutative property, or identity property?
2 + (6 + 8) =(2 + 6)+ _ is it: associated property, commutative property, or identity property?
can someone please help me?
Answer:
_7 + 3 = 3 + 7 : commutative property,[if something is added or subtracted]
0 +5 _ = 5 is it: identity property.[if 0 is added or subtracted]
2 + (6 + 8) =(2 + 6)+ _8 associated property
[if added or multiplied]
Plz help will mark brainliest plz show work!!
Answer:
C 19.2
Step-by-step explanation:
Corresponding parts have the same proportion
x/24 = 20.8/26
multiply both sides by 24
x = 20.8/26 * 24
x = 19.2
Answer:
C
Step-by-step explanation:
Since the triangles are similar then the ratios of corresponding sides are equal, that is
[tex]\frac{AC}{DF}[/tex] = [tex]\frac{AB}{DE}[/tex] , substitute values
[tex]\frac{x}{24}[/tex] = [tex]\frac{20.8}{26}[/tex] ( cross- multiply )
26x = 499.2 ( divide both sides by 26 )
x = 19.2 → C
What is the formula for prism
Answer:
The formula for the volume of a triangular prism is:
V=(l)(w)(h)
Where l is the length of the triangle, w is the width of the triangle, and h is the height of the prism
The formula for the volume of a prism is V=Bh , where B is the base area and h is the height. The base of the prism is a rectangle. The length of the rectangle is 9 cm and the width is 7 cm.
Please mark as brainliest if answer is right
Have a great day, be safe and healthy
Thank u
XD
Jake throws a stone off a bridge into the river. The stones height in meters above the water is based on the time in seconds after jake threw the stone. The quadratic equation y=-5^2+10x+15 represents the scenario
Answer:
The stone will hit the water after 3 seconds
Step-by-step explanation:
Given
[tex]y = -5x^2 + 10x +15[/tex]
Required
At what time will the stone enter the water
When the stone enters the water;
[tex]y = 0[/tex]
So, we have:
[tex]-5x^2 + 10x +15 = 0[/tex]
Divide through by -5
[tex]x^2 -2x -3 = 0[/tex]
Expand
[tex]x^2 +x -3x -3 = 0[/tex]
Factorize
[tex]x(x +1) -3(x +1) = 0[/tex]
Factor out x + 1
[tex](x -3) (x +1) = 0[/tex]
Solve for x
[tex]x - 3 = 0\ or\ x + 1 = 0[/tex]
[tex]x = 3\ or\ x = -1[/tex]
x (time) cannot be negative.
So:
[tex]x = 3[/tex]
Can someone help me please I am losing my mind
Answer:
5-x
Step-by-step explanation:
you will simplify the eq. it will be (x+8)-(x+8)(x-4)
taking (x+8) as common(1-x+4)
(x+8)(5-x)
A right triangle has side lengths 8 ,15 , 17 and as shown below.
Use these lengths to find TanA, sinA,cosA
Answer:
3
Step-by-step explanation:
25 - 6r = 25 please i really need to know what R is
Answer:
r = 0
1.
25-6r=25
−6r+25=25
2.
− 6r+25 = 25
− 6
ILL GIVE BRAINIEST
HELP PLEASE
Answer:
0.125 ?
Step-by-step explanation:
HELP ME OUT GUYS!!!! Question is in the screenshot below.
Answer:
87.55 [tex]cm^2[/tex]
Step-by-step explanation:
I need help ASAP
For which function and interval can the extreme value theorem be applied?
f (x) = StartFraction x Over (x minus 6) squared EndFraction over the interval [3, 5]
f (x) = StartFraction negative 5 Over 2 (x minus 7) cubed EndFraction over the interval (6, 8)
f(x) = 4 tan(πx) over the interval [0, 1]
f(x) = 3ex + 1 over the interval (1, 3)
Answer:
A) f(x)=x/(x-6)^2 over the interval [3, 5]
Step-by-step explanation:
got it right on edge :) good luck!
Answer:
A
Step-by-step explanation:
got it on edge!!
helppp I’m not good with this stuff lol
Answer:
that is you my question is wrong for me
PLEASE HELP ME WITH THIS ALGEBRA PROBLEM!!
Answer:
Solution given.
centre (h,k):(-6,1)
radius (r)=2
we have
equation of a circle is:
(x-h)²+(y-k)²=r²
(x+6)²+(y-1)²=2²
(x+6)²+(y-1)²=4 is a required equation of a circle.
The sum of three consecutive integers is 9. What is the equation that represents the scenario?
a.n + (n + 1) + (n + 2) = 9
b.n – (n + 1) – (n + 2) = 9
c.n + (n – 1) + (n – 2) = 9
d.n=9
Answer:
a is correct ................
If I multiply the number by 4 and then subtract 1, I get the same answer and then add 9
*The number is x
Write it as an equation.
Answer:
12 .
Step-by-step explanation:
12
Janet had 42 marbles. ⅚ of them were blue. The rest were red. How many marbles were blue?
Answer:
35 marbles were blue
Step-by-step explanation:
42/6 = 7
7 x 5 = 35