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Maslowich
3 years ago
15

a metal alloy weighing 3 mg and containing 40% copper is melted and mixed with 2 mg of pure copper. what percent of the resultin

g allot is copper?
Mathematics
1 answer:
Oduvanchick [21]3 years ago
4 0
64%, because 40% of 60% is 24%, and 2 mg of pure copper is 40% of the overall alloy, so add 24 and 40
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Dafna11 [192]

Answer:

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4 0
3 years ago
Q19. When a resistor is placed across 230M supply (de) the
Vera_Pavlovna [14]

The value of the resistor that must be connected in parallel is 57.47 ohms

<h3>How to determine the resistor connected across the 230 V supply</h3>
  • Voltage (V) = 230 V
  • Current (I) = 12 A
  • Resistor 1 (R₁) =?

V = IR

230 = 12 × R₁

Divide both sides by 12

R₁ = 230 / 12

R₁ = 19.17 ohms

<h3>How to determine the total resistance</h3>
  • Voltage (V) = 230 V
  • Current (I) = 16 A
  • Total resistance (Rₜ) =?

V = IR

230 = 16 × Rₜ

Divide both sides by 12

Rₜ = 230 / 16

Rₜ = 14.375 ohms

<h3>How to determine the resistor connected in paralle</h3>
  • Resistor 1 (R₁) = 19.17 ohms
  • Total resistance (Rₜ) = 14.375 ohms
  • Resistor 2 (R₂) = ?

1/Rₜ = 1/R₁ + 1/R₂

Collect like terms

1/R₂ = 1/Rₜ - 1/R₁

R₂ = (Rₜ × R₁) / (R₁ - Rₜ)

R₂ = (14.375 × 19.17) / (19.17 - 14.375)

R₂ = 57.47 ohms

Learn more about Ohm's law:

brainly.com/question/796939

#SPJ1

6 0
2 years ago
— 2x — 6 = 3x — 21<br><br> Help me anyone
stich3 [128]

Answer:

Step-by-step explanation:

-2x+3x=-21+6

or x=-15

3 0
3 years ago
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What is 935 divided by 9?
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103 with a remainder of 8
7 0
3 years ago
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Suppose 40% of DC area adults have traveled outside of the United States. Nardole wants to know if his customers are atypical in
Sonbull [250]

Answer:

We conclude that % of DC area adults who have traveled outside of the United States is different from 40%.

Step-by-step explanation:

We are given that 40% of DC area adults have traveled outside of the United States. Nardole wants to know if his customers are typical in this respect. He surveys 40 customers and finds 60% have traveled outside of the U.S.

We have to test is this result a statistically significant difference.

<em>Let p = % of DC area adults who have traveled outside of the United States</em>

SO, Null Hypothesis, H_0 : p = 40%  {means that 40% of DC area adults have traveled outside of the United States}

Alternate Hypothesis, H_a : p \neq 40%  {means that % of DC area adults who have traveled outside of the United States is different from 40%}

The test statistics that will be used here is <u>One-sample z proportion statistics</u>;

                  T.S. = \frac{\hat p-p}{\sqrt{\frac{\hat p(1- \hat p)}{n} } }  ~ N(0,1)

where, \hat p = % of customers who have traveled outside of the United States

                  in a survey of 40 customers = 60%

          n  = sample of customers = 40

So, <u>test statistics</u> = \frac{0.60-0.40}{\sqrt{\frac{0.60(1-0.60)}{40} } }

                             = 2.582

<em>Since in the question we are not given with the significance level so we assume it to be 5%. So, at 0.05 level of significance, the z table gives critical value of 1.96 for two-tailed test. Since our test statistics is more than the critical value of z so we have sufficient evidence to reject null hypothesis as it will fall in the rejection region.</em>

Therefore, we conclude that % of DC area adults who have traveled outside of the United States is different from 40%.

7 0
3 years ago
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