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Morgarella [4.7K]
2 years ago
10

The amount and the concentration of a salt solution is given. How much salt would you get if you evaporated all water from this

solution?
80g of a 35% solution

The amount and the concentration of a salt solution is given. How much salt would you get if you evaporated all water from this solution?

Im really desperate, I will make you brainliest if u answer both of them correctly
20g of a 17% solution
Mathematics
1 answer:
Gnoma [55]2 years ago
7 0

Answer:

  • 28 g
  • 3.4 g

Step-by-step explanation:

These problems only make sense if the percentage is by weight. To find the amount of salt, multiply the amount of solution by the percentage that is salt:

a) (80 g)(35%) = 28 g . . . . weight of salt

__

b) (20 g)(17%) = 3.4 g . . . . weight of salt

_____

<em>Comment on percent</em>

You know that % means /100, so 35% = 35/100 = 0.35.

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Heidi is saving for a new bike. She has already saved $57. If Heidi earns
PtichkaEL [24]

Answer:

8 hours

Step-by-step explanation:

57 + 9h = 129

9h = 72

h = 8

7 0
2 years ago
Read 2 more answers
Find the real numbers x and y if -3+ix^2y and x^2+y+4i are conjugate of each other. Pls solve with the steps
Firdavs [7]
ANSWER
x = ±1 and y = -4.
Either x = +1 or x = -1 will work

EXPLANATION
If -3 + ix²y and x² + y + 4i are complex conjugates, then one of them can be written in the form a + bi and the other in the form a - bi. In other words, between conjugates, the imaginary parts are same in absolute value but different in sign (b and -b). The real parts are the same

For -3 + ix²y
⇒ real part: -3
⇒ imaginary part: x²y

For x² + y + 4i
⇒ real part: x² + y (since x, y are real numbers)
⇒ imaginary part: 4

Therefore, for the two expressions to be conjugates, we must satisfy the two conditions. 

Condition 1: Imaginary parts are same in absolute value but different in sign. We can set the imaginary part of -3 + ix²y to be the negative imaginary part of x² + y + 4i so that the 

   x²y = -4 ... (I)

Condition 2: Real parts are the same

   x² + y = -3 ... (II)

We have a system of equations since both conditions must be satisfied

   x²y = -4 ... (I)
   x² + y = -3 ... (II)

We can rearrange equation (II) so that we have

   y = -3 - x² ... (II)

Substituting into equation (I)

   x²y = -4 ... (I)
   x²(-3 - x²) = -4
   -3x² - x⁴ = -4
   x⁴ + 3x² - 4 = 0
   (x² + 4)(x² - 1) = 0
   (x² + 4)(x-1)(x+1) = 0

Therefore, x = ±1.
Leave alone (x² + 4) as it gives no real solutions.

Solve for y:

   y = -3 - x² ... (II)
   y = -3 - (±1)²
   y = -3 - 1
   y = -4

So x = ±1 and y = -4. We can confirm this results in conjugates by substituting into the expressions:

   -3 + ix²y 
   = -3 + i(±1)²(-4)
   = -3 - 4i

   x² + y + 4i
   = (±1)² - 4 + 4i
   = 1 - 4 + 4i
   = -3 + 4i

They result in conjugates
4 0
2 years ago
Read 2 more answers
for a population of 800000 subway riders, the numbers of subway trips taken per rider last january are approximately normally di
vladimir1956 [14]
So, we have
<span>Z=<span><span>x−μ / </span>σ

</span></span><span>Mean would be = 56
  30 - 56 = |-26| 4
3 - 56 = |-13|
 and
Standard deviation= 13
</span><span>2 - 1 will give us the approximate area
  95/2 - 68/2 = N

   95 -68 = 27

 27 /2 = 13.5
</span>Hence, the answer would be
<span>800,000 * .135
</span>= <span> 108000</span>
4 0
2 years ago
What’s 8/15 divided by 4/5
iragen [17]

Answer: 2/3

Step-by-step explanation: In this problem, we have 8/15 ÷ 4/5. Dividing by a fraction is the same as multiplying by its reciprocal. In other words, we can change the division sign to multiplication and flip the second fraction.

8/15 ÷ 4/5 can be rewritten as 8/15 × 5/4

Now, we are simply multiplying fractions so we multiply across the numerators and multiply across the denominators.

8/15 × 5/4 = 40/60 = 2/3

8 0
2 years ago
A math teacher tells her students that eating a healthy breakfast on a test day will help their brain function and perform well
kogti [31]

Answer:

Step-by-step explanation:

Hello!

To test the claim that eating a healthy breakfast improves the performance of students on their test a math teacher randomly asked 46 students what did they have for breakfast before they took the final exam and classified them as:

<u>Group 1</u>: Ate healthy breakfast

X₁: Number of students that ate a healthy breakfast before the exam and earned 80% or higher.

n₁= 26

<u>Group 2: </u>Did not eat healthy breakfast

X₂: Number of students that did not eat a healthy breakfast before the exam and earned 80% or higher.

n₂= 20

After the test she counted the number of students that got 80% or more in the test for each group obtaining the following sample proportions:

p'₁= 0.50

p'₂= 0.40

The parameters of study are the population proportions, if the claim is true then p₁ > p₂

And you can determine the hypotheses as

H₀: p₁ ≤ p₂

H₁: p₁ > p₂

α: 0.05

Z= \frac{(p'_1-p'_2)-(p_1-p_2)}{\sqrt{p'(1-p')[\frac{1}{n_1} +\frac{1}{n_2}] } } }≈N(0;1)

pooled sample proportion: p'= \frac{x_1+x_2}{n_1+n_2} =\frac{13+8}{46} = 0.46

Z_{H_0}= \frac{(0.5-0.4)-0}{\sqrt{0.46(1-0.46)[\frac{1}{26} +\frac{1}{20}] } } }= 0.67

p-value: 0.2514

The decision rule is:

If p-value ≤ α, reject the null hypothesis.

If p-value > α, do not reject the null hypothesis.

The p-value: 0.2514 is greater than the significance level 0.05, the test is not significant.

At a 5% significance level you can conclude that the population proportion of math students that obtained at least 80% in the test and had a healthy breakfast is equal or less than the population proportion of math students that obtained at least 80% in the test and didn't have a healthy breakfast.

So having a healthy breakfast doesn't seem to improve the grades of students.

I hope this helps!

5 0
2 years ago
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