1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
almond37 [142]
3 years ago
7

HELP ASAP PLEASEE!! a metal alloy weighing 4 mg and containing 20% iron is melted and mixed with 12 mg of a different alloy whic

h contains 40% iron. which percent of the resulting alloy is iron?
A)12%

B)20%

C)35%

D)55%
Mathematics
1 answer:
saul85 [17]3 years ago
4 0

Answer:

35 percent

Step-by-step explanation:

To solve this problem we multiply the amount by the percent and add them up to get the total amount times the percent

amount * percent + amount * percent = total amount * percent

4  * .20 + 12  * .40 = (4+12) * x

.8 + 4.8 = 16 x

Combine like terms

5.6 = 16x

Divide by 16

5.6/16 = 16x/16

.35 =x

35 percent


You might be interested in
7x-2y=-5which ordered pair is a solution of the equation
sashaice [31]

Answer:

What ordered pair my closest answer is y = 5/2+7x/2

Step-by-step explanation:

Subtract 7x from both sides of the equation.

3 0
2 years ago
Suppose you deposit $1000 in a college fund that pays 7.2% interest compounded
SSSSS [86.1K]

Answer: A = P(1 + r/n)nt

= $1415.71

7 0
3 years ago
Trey and Brandon each bought a new hockey stick for $80.
Gre4nikov [31]

Answer:

$4

Step-by-step explanation:

Trey sold his $80 hockey stick for 25% less. This means that he received 75% of the $80. Convert the percentage to a decimal, so it will be .75. Multiple .75 by $80 and you will get the final answer which is $60.

Brandon sold his $80 hockey stick for 30% less. This means that he received 70% of the $80. Convert the percentage to a decimal, so it will be .70. Multiple .70 by $80 and you will get the final answer which is $56.

Trey received $4 more for his hockey stick.

5 0
2 years ago
Question is in screenshot. Please answer it correctly
fomenos

a) You need to sell 12 or 29 dresses.

b) Any number between 2 and 39 dresses will give a positive profit.

<h3>How many dresses must be sold in order to make a profit of 3000 euros?</h3>

Here we know that the profit, in euros, as a function of the number of dresses sold is:

P(x) = -11*x^2 + 450*x - 800

Now, if you want to find how many dresses you need to sell to have a profit of 3000 euros, then you need to solve:

P(x) = 3000 = -11*x^2 + 450*x - 800

So we need to solve the quadratic equation:

-11x^2 + 450x - 800 - 3000 = 0

-11x^2 + 450x - 3800 = 0

The solutions are given by Bhaskara's formula:

x = (-450 ± √(450^2 - 4*(-3800)*(-11))/2*(-11)

x = (-450 ± 187.9)/(-22)

We have two solutions that give the same profit:

  • x = (-450 + 187.9)/-22 = 11.9 that can be rounded to 12.
  • x = (-450 - 187.9)/-22 = 28.99 that can be rounded 29.

Then if you sell either 12 or 29 dresses, you will get a profit of 3000 euros.

b) To make a profit you need to sell more than P = 0, so let's solve that first:

P= 0 = -11*x^2 + 450*x - 800

The solutions are:

x = (-450  ± √(450^2 - 4*(-800)*(-11))/2*(-11)

x = (-450  ± 409)/(-22)

The smaller solution is:

x = (-450 + 409)/-22 = 1.86 that can be rounded to 2.

(because you can't sell 1.86 of a dress)

The other solution is:

x =  (-450 - 409)/-22 = 39

So, between 2 and 39 dresses, you will make a profit.

If you want to learn more about quadratic equations:

brainly.com/question/1214333

#SPJ1

6 0
1 year ago
The realtor and her clients do not know the average home sale price for all of Guelph (500 was actually just a guess). However,
strojnjashka [21]

Answer:

a) The 99% confidence interval would be given by (346.708;453.292)

b) The 99% confidence interval would be given by (338.445;461.555)

Step-by-step explanation:

1) Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

\bar X=400 represent the sample mean for the sample  

\mu population mean (variable of interest)

\sigma=80 represent the population standard deviation

n=15 represent the sample size  

2) Part a

The confidence interval for the mean is given by the following formula:

\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}   (1)

Since the Confidence is 0.99 or 99%, the value of \alpha=0.01 and \alpha/2 =0.005, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that z_{\alpha/2}=2.58

Now we have everything in order to replace into formula (1):

400-2.58\frac{80}{\sqrt{15}}=346.708    

400+2.58\frac{80}{\sqrt{15}}=453.292

So on this case the 99% confidence interval would be given by (346.708;453.292)    

3) Part b

For this case we don't know the population deviation so we need to use the t distribution instead the normal standard distribution.

The confidence interval for the mean is given by the following formula:

\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}   (1)

We need to find the degrees of freedom first df=n-1=15-1=14

Since the Confidence is 0.99 or 99%, the value of \alpha=0.01 and \alpha/2 =0.005, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,14)".And we see that t_{\alpha/2}=2.98

Now we have everything in order to replace into formula (1):

400-2.98\frac{80}{\sqrt{15}}=338.445    

400+2.98\frac{80}{\sqrt{15}}=461.555

So on this case the 99% confidence interval would be given by (338.445;461.555)    

4 0
2 years ago
Other questions:
  • A city manager wants to add a playground in a new city park. The rectangle below represents the plan for the dimensions of the r
    15·1 answer
  • How many different triangles can you make if you are given these two lengths for sides?
    13·2 answers
  • Measures of variability are used to characterize how the data are _____ around the _____ of the distribution.
    15·1 answer
  • Please help! Correct answers only please!
    7·1 answer
  • Seraphina is driving two hours to visit her family. For the first hour, she traveled at a speed of 60 miles per hour. Then, in t
    5·1 answer
  • Solve the following inequality showing all steps -3n+7&lt;4
    10·1 answer
  • PLEASE HELP I WILL GIVE BRAINLIEST <br><br> Which statement accurately describes the scatterplot
    7·2 answers
  • HELP ASAP!!
    12·1 answer
  • If you can solve all parts I will give brainliest (also give strategy)
    6·1 answer
  • The difference of p and 4
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!