An alloy of copper and zinc which contains 5 grams of zinc. If 15 grams of zinc are added to this alloy, a new alloy is obtained in which the copper content has been reduced by 30% from the original. Find the initial mass of the alloy

Answers

Answer 1

Answer:

Initial mass = 25 grams

Step-by-step explanation:

[tex]\left(\frac{x}{x+20}\right)\:=\:\:\left(\frac{x}{x+5}\:-.3\:\right)[/tex]

x = 20 (mass of copper)

[tex]\frac{20}{20+5} = .8 = 80[/tex] percent

[tex]\\\frac{20}{20+15} = .5 = 50[/tex] percent  


Related Questions

9) Three times a number added to 12 gives -6. Find the number.​

Answers

Answer:

The number is -6.

Step-by-step explanation:

Variable x = a number

Set up an equation:

3x + 12 = -6

Isolate variable x:

3x = -18

x = -6

Check your work:

3(-6) + 12 = -6

-18 + 12 = -6

-6 = -6

Correct!

Answer:

3x +12=-6

3x=-6-12

3x=-18

x=-18/3

x=-6

it began 63°F, and the temp changed by 8°F over the course of 6 hours whats the minimum and maximum???

Answers

Answer:

Minimum Possible Temperature: 55° F

Maximum Possible Temperature: 71° F

Step-by-step explanation:

Beginning temperature: 63° F

Change in temperature: 8° F

If the temperature decreased: 63° F - 8 °F = 55° F

If the temperature increased: 63° F + 8° F = 71° F

Minimum Possible Temperature: 55° F

Maximum Possible Temperature: 71° F

Decide !!!!!!!!!!!!!!!!!!

Answers

Make note of the coefficients in the first and fourth equations. They've been conveniently picked so that subtracting one equation from the other eliminates every variable but t. We have

(3r + 2s + t + 2u + 3v) - (3r + 2s + 3t + 2u + 3v) = 7 - 17

-2t = -10

t = 5

A baseball player swings and hits a pop fly straight up in the air to the catcher. The height of the baseball in meters t seconds after it is hit is given by the quadratic function . How long does it take for the baseball to reach its maximum​ height? What is the​ baseball?s maximum​ height?

Answers

Answer:

Step-by-step explanation:

Let the initial velocity of the ball is u.

At the maximum height the speed is zero.

Let the time is t.

Use first equation of motion.

v = u - gt

0 = u - g t

t = u/g

Let the maximum height is H.

Use third equation of motion

[tex]v^2 = u^2 - 2 gh\\\\0 = u^2 - 2 gH\\\\H = \frac{u^2}{2 g}[/tex]

PLZZZ HELPPP!! And also plz explain how to do this too me!! Which of the following numbers listed below are solutions to the equation below check all that apply. √s^2 = s

Answers

Answer:

option E is the correct answer

Answer:

A and B

Step-by-step explanation:

When S is positive S equals itself but when S is a negative number S turns postive

Example of positive is √7^2=7

example of negative number for S is √-9^2=9 NOT -9

What is the value of g(f(x)) f(x)=2x^2+3 g(x)=x-4

Answers

Answer:

2x^2 -1

Step-by-step explanation:

f(x)=2x^2+3

g(x)=x-4

g(f(x))

Replace x in g(x) with the function f(x)

g(f(x)) = 2x^2+3 -4

Combine like terms

         =2x^2 -1

How many solutions are there to the equations: x+2y=-2 y=1/2x-5

Answers

Answer:

Step-by-step explanation:

x+2y=-2

2y=-x-2

y=-x/2-2/2

y=-x/2-------(1)

y=1/2x-5-----(2)

(1)=(2)

-x/2=1/2x-5

-x=x-10

-2x=-10

x=5

substitute in 2

         y=(1/2)*5-5

           =5/2-5

          =-2.5

Apply the dristrbutie property to factor out the greatest common factor of 9a-18b+21c

Answers

Answer:

3 (3a-6b+7c)

Step-by-step explanation:

Answer:

Step-by-step explanation:

The highest common factor is 3.

9/3 = 3

18/3 =6

21/3 = 7

The literals have no common factors that we know of.

Answer: 3(3a - 6b + 7c)


FIND AC! PLS HELP!!

Answers

Answer:

AC = 7.3 in

Step-by-step explanation:

tan(51°) = 9/AC

1.24 = 9/AC

AC = 9/1.24

AC = 7.26

Uma maneira de realizar a operação 9972 - 9 de forma rápida e correta é calculando 1 000 * 994, que é igual a 994 000. A igualdade que justifica esse fato está expressa em:

a) (a + b)² = a² + b² + 2ab
//
b) a² - b² = (a + b)(a - b)
//
c) a² - b² = (a - b)²
//
d) (a - b)² = a² - 2ab + b²
//
e) a² - b² = 1 000(a + b)

Answers

Answer:

a)

Step-by-step explanation:

Name the property shown by the statement a + (b + 2) = (a + b) + 2

Answers

Answer:

The associative property

Step-by-step explanation:

In brief terms, the associative property states that when one has like operations, or an operation and its inverse, one can add parenthesis to the equation without changing the final answer. One can also change the place in which the parenthesis stands in this expression without altering the result. remember, an operation and its inverse refers to any operation and the operation that is done to undo the operation. The following is a list of such operations:

[tex]x^n=b[/tex]        [tex]\sqrt[n]{b}=x[/tex]

[tex]a*b[/tex]            [tex]a[/tex] ÷ [tex]b[/tex]

[tex]a+b[/tex]           [tex]a-b[/tex]

Prove that 1/√2 is irrational

Answers

Answer:

Step-by-step explanation:

Let's assume that it is rational , so this number can be represented as

[tex]\Large \boldsymbol{}\bf \dfrac{p^{^/is \ an \ integer}}{q^{ / natural}} -irreducible \ \ fraction[/tex]

[tex]\Large \boldsymbol{}\bf \dfrac{1 ^{/ an \ integer }}{\sqrt{2}^{ / not \ \ integer } }[/tex]  -Since the denominator is not a natural number then the  1/√2   is respectively an irrational number

Estimate 2371 x1.84 divide 36.92

Answers

Answer:

Step-by-step explanation:

2371 x1.84 = 4362

4362 ÷ 36.92 = 118

the answer would be 118.1646804 but since the lowest sig fig in the question is 3 (1.84), we would have to round the answer to 3 SIG figs.

Final answer: 118

Jan has three times as many marbles as Liana. If Jan gives 3 of her marbles to Liana,
they will have the same number. How many marbles do they have between them?
(A) 18
(B) 6
(C) 8
(E) 16

Answers

Answer:

Step-by-step explanation:

I got 12 so not sure.

3x-3=x+3

2x=6

X=3

So 3x3 =9. +3. =12

Can anyone help plz?

Answers

Answer:

just add a small amount and and square the new number

between 2.82 and 2.83 seems a bit closer

Step-by-step explanation:

x      x^2

2.8         7.84

2.81         7.8961

2.82 7.9524

2.83 8.0089

2.84 8.0656

2.85 8.1225

2.86 8.1796

2.87         8.2369

simplify 1+tan^2x÷1+tan^2x​

Answers

Answer:

uihuii

Step-by-step explanation:

Geometry, please answer question ASAP

Answers

Answer:

I think the shape above has an order of 5 because it has a reflectional symmetry of 5.

I hope this helps

I believe it is choice C. order 5

HELP PLEASE

A tuning fork with a period of 1.95 x 10-3 is struck at the same time as a guitar
string. If 24 beats are heard in 6.0 s, find the possible frequency or frequencies of the guitar string.

Answers

Answer:

The possible approximate frequencies of the guitar string are 516.82 Hz and 508.82 Hz

Step-by-step explanation:

The given period of the tuning fork, T₁ = 1.95 × 10⁻³ s

The number of beats in 6.0 s = 24 beats

Therefore, the beat frequency, [tex]f_{beat}[/tex] = 4 beats per second = 4 Hz

Let f₁ represent the frequency of the tuning fork, and let f₂ represent the frequency of the guitar string, we have;

f₁ = 1/T₁ = 1/(1.95 × 10⁻³) ≈ 512.82 Hz

We have;

[tex]f_{beat} = \left | f_2 - f_1 \right |[/tex]

[tex]\pm f_{beat} = f_2 - f_1[/tex]

Therefore, we get;

[tex]4 \, Hz= \left | f_2 - 512.82 \, Hz \right |[/tex]

f₂ - 512.82 = ± 4

∴ f₂ = 512.82 ± 4

The possible frequencies of the guitar string,  f₂ ≈ 516.82 Hz or f₂ ≈ 508.82 Hz

Can someone help me out with this

Answers

Diameter=d=23.4in

We know

[tex]\boxed{\Large{\sf Circumference=\pi d}}[/tex]

[tex]\\ \Large\sf\longmapsto Circumference=\dfrac{22}{7}\times 23.4[/tex]

[tex]\\ \Large\sf\longmapsto Circumference=\dfrac{514.8}{7}[/tex]

[tex]\\ \Large\sf\longmapsto Circumference=73.5in[/tex]

To paint a wooden cube, Pinocchio needs 4 grams of paint. When it is dry, he cut the cube into 8 smaller pieces of smaller size. How much paint additional paint does Pinocchio need to paint the unpainted surfaces of the smaller cubes

Answers

Answer:

9 grams of paint

Step-by-step explanation:

6×8=48

48÷4= 12

48-12=36

36÷4=9

first multiply 6 by 8 because a cube has six faces and you cut that cube eight times

second after you cut that you will have 48 faces and for every six faces there are 4 grams of paint so you divide 48 by 4 and you get 12 this means that 12 of the faces are painted

next you subtract 12 from 48 and you get 36 this means that 36 faces are not painted

lastly you divide 36 by 4 and you will get 9 grams of paint

16. PLEASE HELP ME
Solve the equation by factoring.

z2 - 6z - 27 = 0

A. z = 3 or z = 9

B. z = –3 or z = 9

C. z = –3 or z = –9

D. z = 3 or z = –9

Answers

Answer:

B

Step-by-step explanation:

z^2 - 6z - 27 = 0

(z - 9)(z+3) = 0

z - 9 = 0 z + 3 = 0

z = -3, 9

The third one is a solution

i am having problems with this problem.

Answers

Answer:

-70

Step-by-step explanation:

keep adding -4 until you reach the 18th term for example

-2

-6

-10

-14

-18

-22

-26

-30

-34

-38

-42

-46

-50

-54

-58

-62

-66

-70

Find the missing angle. PLS HELP FAST !

Answers

Answer:

x = 53.5°

Hope this helps... Have a good day!!

Quad DEFG with mZD= (12x - 4),
mZE = (18x + 4)ºmZF = (15x + 10), and
m2G= (5x)
What is the value of x?

Answers

Answer: x = 7°

Explanation:

We know that sum of angles of a quadilateral is = 360°

Therefore ATQ

⇒ (12x-4)+(18x+4)+(15x+10)+(5x) = 360

⇒ (12x + 18x + 15x + 5x) + (-4+4+10) = 360

⇒ 50x + 10 = 360

⇒ 50x = 360-10

⇒ 50x = 350

⇒ x = 350/50

⇒ x = 7

Therefore value of x is 7°

Must click thanks and mark brainliest

traders fix the price of cosmetic items 30% above the cost price when he sold an item at 25% discount there was a loss of Rs 15 find the cost price and marked price of the item​

Answers

Cost price is Rs600 and marked price is Rs780.

Must click thanks and mark brainliest

Can someone help with these 2?

Answers

Answer:

a. 25 ft squared

b. 0.3

Step-by-step explanation:

a. if the perimeter is 20 that means that each side would be 5 because its a square and 5 x 5 is 25.

b. 0.3 to the third power is 0.027

Write an algebraic expression for each verbal expression. 1.One third of a number is twelve less than the number itself 2. Two times the sum of a number and five is twenty

Answers

Answer:

1. ⅓*m = m - 12

2. 2(a + 5) = 20

Step-by-step explanation:

1. Let the number be represented by m

Let one-third of the number m, be ⅓*m

If there is 12 less of an amount of something, it implies 12 is to be subtracted from the initial amount.

Thus, 12 less than the number, m is (m - 12)

》⅓*m = m - 12

2. Let the number be represented by a

The sum of the number and 5 is (a+5)

》2(a+5) = 20

What is the numerical Absolute values of -16

Answers

Answer:

16

Step-by-step explanation:

The absolute value always gives a positive value , that is

| - a | = | a | = a , then

| - 16 | = | 16 | = 16

Part A
The poll report includes a table titled, “Americans Using Cash Now Versus Five Years Ago, by Age.” The age intervals are not equal. Why do you think the Gallup organization chose the age intervals of 23–34, 35–54, and 55+ to display these results?

Answers

Answer:

These are the intervals of the people who are at least adults and are mature enough to take the survey seriously and answer correctly

Step-by-step explanation:

4. Which property of similarity can be used to prove triangles DEF and GHI are similar?

Answers

Answer:

SSS

Step-by-step explanation:

We know all three sides of both triangles. The common ratio of DEF to GHI is 2/3.

Answer:

SSS

Step-by-step explanation:

Similar triangles must have congruent corresponding angles and proportional corresponding sides.

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