Answer:
Jack needs 6 hours and Jill needs 3 hours.
Step-by-step explanation:
Let's define the variables:
X = rate at which Jack can write a holiday card.
Y = rate at which Jill can write a holiday card.
Each of them will need a given time to write a card, such that:
X*T = 1 card
We know that Jack needs 3 more hours to write a card than Jill, then Jill needs 3 hours less than Jack, so if Jack needs T hours, Jill will need T - 3 hours
Then we have the equation:
Y*(T - 3 hr) = 1 card
And we also know that when they work together, they need 2 hours, then:
(X + Y)*2 hr = 1 card.
So we have 3 equations:
X*T = 1 card
Y*(T - 3 hr) = 1 card
(X + Y)*2 hr = 1 card.
Now let's ignore the card part just for the equations, then we get:
X*T = 1
Y*(T - 3 hr) = 1
(X + Y)*2 hr = 1
To solve it, we first need to isolate one variable in one of the equations, let's isolate T in the first equation, we get:
T = 1/X
Now we can replace this in the second equation to get:
Y*((1/X) - 3hr) = 1
So now we have two equations:
(X + Y)*2 hr = 1
Y*((1/X) - 3hr) = 1
We need to do the same, isolate one variable in one of the equations, let's isolate Y in the above one:
Y*2hr = 1 - X*2hr
Y = (1 - X*2hr)/2hr
Now we can replace this in the other equation to get:
((1 - X)/2hr)*((1/X) - 3hr) = 1
Now we can solve this for X:
((1 - X)/2hr)*((1/X) - 3hr) = 1
(1 - X)*((1/X) - 3hr) = 2 hr
1/X - 3hr - X*2hr/X + X*2hr*3hr = 2hr
1/X - 3hr - 2hr + X*6hr^2 = 2hr
1/X + X*6hr^2 = 2hr + 3 hr + 2 hr = 7hr
1/X + X*6hr^2 = 7hr
Now we can multiply all by X to get:
X/X + X*(X*6hr^2) = 7hr*X
Now we have the quadratic equation:
(6hr^2)*X^2 - (7hr)*X + 1 = 0
We can find the solutions of this equation if we use the Bhaskara's formula, the solutions are:
[tex]X = \frac{-(-7hr) +- \sqrt{(-7hr)^2 - 4*(6hr^2)*1} }{2*6hr^2} = \frac{7hr +- 5hr}{12 hr^2}[/tex]
Then we have two solutions:
X = (7hr + 5hr)/12hr = 1 hr^-1
And this is the rate at which Jack writes a card, so the actual units are:
X = 0.167 card/hr
Then Jill's rate will be:
Y = (1 - X*2hr)/2hr = (1 - 1card/hr*2hr)/2hr = -0.5 card/hr
So we have a negative rate, this makes no sense, so we can discard this option. The other solution for X is:
X = (7hr - 5hr)/12hr = 0.166... hr^-1
And this is the rate at which Jack writes a card, so the actual units are:
X = 0.166... card/hr
If we have this, then the rate for Jill will be:
Y = Y = (1 - X*2hr)/2hr = (1 - 0.167card/hr*2hr)/2hr = 0.333 card/hr
Then we have:
X = 0.167 card/hr
If we use the first equation, we get:
(0.166... card/hr)*T = 1 card
T = 1 card/((0.166... card/hr)) = 6 hours
Then Jack needs 6 hours to write a card.
And we know that Jill needs 3 hours less than that, then Jill needs 3 hours.
I need help with this question
Answer:
j-10=35
j is 45
Step-by-step explanation:
35+10=45
Help ASAP Draw a tape diagram representing the following situation. You may need to decide what to present with a variable.
At an athletic banquet, an equal number of athletes were seaterd at each of the 7 large tables, and 24 parents were seated together on the other side of the room. There were 87 guests attending.
Answer:9
Step-by-step explanation:87-24=63 and 63 divided by 7 equals 9
12 more than the square of a number is the same as 7 times the number.
Answer: Sorry I don't know
Step-by-step explanation:
Sandy spent 20% of x hours at her part-time job.What is x if 20% of x is about 26 hours?
if 3/4 of a certain number is equal to 4 1/2, find the number
Answer:
6
Step-by-step explanation:
3/4x = 9/2
4/3 * 9/2 = 36/6
6
The number in the mathematical statement is 6
How to determine the number?Let the number be x.
So, the equation can be represented as:
3/4 * x = 4 1/2
Express the fraction as an improper fraction
3/4 * x = 9/2
Multiply through by 4/3
x = 6
Hence, the number is 6
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Sarah is going to invest $8,600 and leave it in an account for 16 years. Assuming the
interest is compounded annually, what interest rate, to the nearest tenth of a percent,
would be required in order for Sarah to end up with $18,500?
Answer:
4.9%
Step-by-step explanation:
exact volume of this cylinder
I am taking this quiz but I'm pretty sure its....c
Answer:
Volume=πr2h=π·42·8≈402.12386
Step-by-step explanation:
What is the AREA of the given circle?
62.83 in²
157.08in²
314.16 in²
628.32 in²
Answer:
314.16 in²
Step-by-step explanation:
Answer:
[tex]A[/tex] ≈ [tex]314.16[/tex]
Step-by-step explanation:
[tex]A=\pi r^2[/tex]
[tex]A = \pi (10)^2[/tex]
[tex]A = \pi (100)[/tex]
[tex]A[/tex] ≈ [tex]314.16[/tex]
Write out the form of the partial fraction decomposition of the function (as in this example). Do not determine the numerical values of the coefficients. (a) x − 20 x2 + x − 20 Incorrect: Your answer is incorrect. (b) x2 x2 + x + 20 Incorrect: Your answer is incorrect.
Answer:
[tex]\frac{x - 20}{ x^2 + x - 20} = \frac{5}{9(x-4)}+\frac{4}{(x+5)}[/tex]
Step-by-step explanation:
Given
[tex]\frac{x - 20}{ x^2 + x - 20}[/tex]
Required
Decompose into partial fraction
Start by factorizing the denominator:
[tex]x^2 + x - 20 =x^2 + 5x -4x- 20[/tex]
[tex]x^2 + x - 20 =x(x + 5)-4(x+5)[/tex]
[tex]x^2 + x - 20 =(x-4)(x+5)[/tex]
So, we have:
[tex]\frac{x - 20}{ x^2 + x - 20} = \frac{A}{x-4}+\frac{B}{x+5}[/tex]
Take LCM
[tex]\frac{x - 20}{ x^2 + x - 20} = \frac{A(x+5)+B(x-4)}{(x-4)(x+5)}[/tex]
Cancel out the denominator
[tex]x - 20 = A(x+5)+B(x-4)}[/tex]
Open brackets
[tex]x - 20 = Ax+5A+Bx-4B[/tex]
Collect Like Terms
[tex]x - 20 = Ax+Bx+5A-4B[/tex]
[tex]x - 20 = (A+B)x+5A-4B[/tex]
By comparison;
[tex](A +B)x = x[/tex] ==>[tex]A + B = 1[/tex]
[tex]5A - 4B = 1[/tex]
Make A the subject in [tex]A + B = 1[/tex]
[tex]A = 1 - B[/tex]
Substitute 1 - B for A in [tex]5A - 4B = 1[/tex]
[tex]5(1-B) -4B = 1[/tex]
[tex]5-5B -4B = 1[/tex]
[tex]5-9B = 1[/tex]
Collect Like Terms
[tex]-9B = 1 - 5[/tex]
[tex]-9B = - 4[/tex]
[tex]B = \frac{4}{9}[/tex]
[tex]A = 1 - B[/tex]
[tex]A = 1 - \frac{4}{9}[/tex]
[tex]A = \frac{9-4}{9}[/tex]
[tex]A = \frac{5}{9}[/tex]
So:
[tex]\frac{x - 20}{ x^2 + x - 20} = \frac{A}{x-4}+\frac{B}{x+5}[/tex]
[tex]\frac{x - 20}{ x^2 + x - 20} = \frac{5}{9(x-4)}+\frac{4}{(x+5)}[/tex]
Terrell brought $5.00 to spend at the rink's concession stand. Hot dogs cost $0.65, French fries cost $0.80, nachos cost $1.25, and drinks cost $0.95. If Terrell buys French fries and a drink, what is the maximum number of hot dogs he can purchase?
Answer:
5 hotdogs
Step-by-step explanation:
Deduct the price of French fries + drink from the total amount of money he has.
5.00 - 0.80 - 0.95 = 3.25
Divide the amount of money left with the amount of money each hotdog cost.
3.25 ÷ 0.65 = 5
How many times greater is the area of Circle 1 than the area of Circle 2?If circle ones radius is 9 and circle twos radius is 3
It is 9 fr 100% pls trust me
The area of the circle {1} is 9 times greater than circle {2}.
What is Area?
Area is a collection of two - dimensional points enclosed by a single dimensional line. Mathematically, we can write -
V = ∫∫F(x, y) dx dy
Given is to find how many times greater is the area of circle 1 than the area of circle 2 if circle ones radius is 9 and circle twos radius is 3.
We can write the areas of both the circles as -
A{Ο} = πR²
A{Ο1} = π x 9 x 9
A{Ο2} = π x 3 x 3
We can write -
A{Ο1} / A{Ο2} = {π x 9 x 9} / {π x 3 x 3}
A{Ο1} / A{Ο2} = 9
A{Ο1} = 9A{Ο2}
Therefore, the area of the circle {1} is 9 times greater than circle {2}.
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Sorry if the picture is scuffed. Pls help fast
Answer:
C
Step-by-step explanation:
the domain would be all positive real numbers, including zero
Simplify (3^z)^6 in exponent notation
Answer:
3^6z
Step-by-step explanation:
you multiply 6 and z since they are exponets and one is in a (
Answer:
3 to the power of 6z of 3^6z
Step-by-step explanation:
5 for $4.45 or 8 for $7.28
Answer:
5 for $4.45
Step-by-step explanation:
a. Find the value of x
below
#The x side is same with 80° so
11x + 3 = 80°
11x = 80 - 3
11x = 77
x = 7
Answer : 7Skylas research Shows at eight empty cans make 1/ 4th pound of aluminum
she
wants to know how many cans it takes to make 5 pounds of aluminum how many kids are there per pound of aluminum
Answer:
160 cans for 5 pounds of aluminum
Step-by-step explanation:
how many odd _2-digit positive integers can be written using the numbers 2,4,5, and 8?
Answer:
4 different odd integers: 25, 45, 55, 85
Step-by-step explanation:
hitunglah luas permukaan balok dengan ukuran sebagai berikut
a. 8 cm × 4 cm × 2cm
B. 8 cm × 3 cm × 4 cm
jawaban
a. = 112 cm²b. = 136 cm²penjelasan langkah demi langkah( step by step explanation )
Total Luas Permukaan = 2 (Panjang x Lebar + Lebar x Tinggi + Panjang x Tinggi)
a.Luas Permukaan = 2( 8×4 + 4×2 + 2×8 )
= 2 ( 32 + 8 + 16 )
= 2 × 56
= 112 cm²b.Luas Permukaan = 2( 8×3 + 3×4 + 4×8 )
= 2 ( 24 + 12 + 32 )
= 2 × 68
= 136 cm²
What is the property of 4x+6=18
Answer: 4x-6= 18
4x=24
x= 24 & 4
x=6
Step-by-step explanation:
Answer:
x = 3
Step-by-step explanation:
I'm not exactly sure of what you mean by property but I think it might be associative property of multiplication?
But to solve for x you would subtract 6 from 18 which gives your 12. Then you divide by 4 to get the x alone and 12/4 is 3.
can someone pls just give me a simple answer -6(2z - 4) use Z = 3
Answer:
12
ignore this i have to put words in to give u the answer
Answer:
-6 (this is easy math)
Please help me with this question what’s 84 + 6 1/3
Answer:
90 1/3
Step-by-step explanation:
Answer: Mixed number form = 90 1/3
Decimal form = 90.3 with a repation bar
Actual Form = 271 / 3
Step-by-step explanation:
T-shirts are on sale for 40% off. The original price per t-shirt is $20. What is the total cost, in dollars, of 8 of these t-shirts at the sale price, including an 11% sales tax?
Answer:
$106.56
Step-by-step explanation:
discounted price of each shirt is $12
12 x 8 = $96 for 8 shirt
96 x 1.11 = $106.56
what is the quotient of 0.6÷243
Answer:
the answer is 0.0024
Step-by-step explanation:
there are more digit's after 4 but hope this is enough
Solve the inequality:
15 ≤ 3 − 2x
Divide both sides by 2
2.2 Subtract 6 from both sides
x ≤ -6
2.000 X + 12.000 ≤ 0
Answer: x ≤ -6
Lizette earns $10 in gas money for driving to babysit and then earns $8 for each hour she
babysits the kids. How much money will she make for 5 hours of babysitting?
Answer:
$30
Step-by-step explanation:
8 x 5 = 40
40 - 10 = 30
One number is 9 more than twice the other number. Their sum is 54. Find the numbers.
Answer: The Numbers are 15 and 39
Step-by-step explanation: 2(15) + 9 = 39
Two less than three times a number
Answer:
3x-2
Step-by-step explanation:
3 times a number is 3x, if we use x as the number
Two less than (3x) is 3x - 2
ss of
3. In a class of 50 students, 40 % are girls. Find the number of girls and
number of boys in the class?
Solution:
Answer:
20 boys in the class
Step-by-step explanation:
40% of 50 is 20
A line segment has an endpoint at (-7, 11) and (-6, 4), what is the length of
the segment?
Answer:
d = 5√2 units
Step-by-step explanation:
Let's use the distance formula: d = √[(x₂ - x₁)² + (y₂ - y₁)²]
Plug in the values with your endpoints.
d = √[(-6 - (-7))² + (4 - 11)²]
Solve within the parentheses.
d = √[(1)² + (-7)²]
Solve the exponents.
d = √[1 + 49]
Solve within the brackets.
d = √50
Simplify the square root.
25 • 2 = 50
√25 • √2 = √50
5 • √2 = √50
d = 5√2 units
Hope this helps!
Which of the following is the expansion of
(2x + 3)^3?
I think the answer is 8×^3+36×^3+54×+27. If the answer is wrong then I'm sorry
Answer:
8x^3 + 36x^3 + 54x + 27
Step-by-step explanation:
If you're asking to expand the equation the answer is 8x^3 + 36x^3 + 54x + 27