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2 years ago

C and d for 20 pts aaaaaaaaaaaaaaaaa

Mathematics

2 answers:

kiruha [24]2 years ago

8 0

Answer:

C. a = 7

D. c = -3

Step-by-step explanation:

C. 7(2a + 3) + 21 = 100+ 40

14a + 21 + 21 = 140

14a = 140 - 21 - 21

14a = 98

a = 7

D. 6+ 14 - 12c = 56

20 - 12c = 56

-12c = 56 - 20

-12c = 36

c = - 3

blsea [12.9K]2 years ago

3 0

Answer:

Step-by-step explanation:

c.7(2a+3)+21=100+40

14a+21+21=140

14a+42=140

14a=140-42

a=98/14

a=7

d.6+14-12c=56

20-12c=56

-12c=56-20

c=36/-12

c=-3

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Find the quotient 2758 divided by 28

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2 years ago

What are the vertices of /(△)?

Serga [27]

Answer:

Step-by-step explanation:

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3 years ago

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The time needed to complete a final examination in a particular college course is normallydistributed with a mean of 80 minutes

Artist 52 [7]

Answer:

a) 0.023

b) 0.286

c) 10 students will be unable to complete the exam inthe allotted time.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 80 minutes

Standard Deviation, σ = 10 minutes

We are given that the distribution of time to complete an exam is a bell shaped distribution that is a normal distribution.

Formula:

$z_{score} = \displaystyle\frac{x-\mu}{\sigma}$

a) P(completing the exam in one hour or less)

P(x < 60)

$P( x < 60) = P( z < \displaystyle\frac{60 - 80}{10}) = P(z < -2)$

Calculation the value from standard normal z table, we have,

$P(x < 60) =0.023= 2.3\%$

b) P(complete the exam in more than 60 minutes but less than 75 minutes)

$P(60 \leq x \leq 75) = P(\displaystyle\frac{60 - 80}{10} \leq z \leq \displaystyle\frac{75-80}{10}) = P(-2 \leq z \leq -0.5)\\\\= P(z \leq -0.5) - P(z < -2)\\= 0.309- 0.023 = 0.286= 28.6\%$

c) P(completing the exam in more than 90 minutes)

P(x > 90)

$P( x > 90) = P( z > \displaystyle\frac{90 -80}{10}) = P(z > 1)$

$= 1 - P(z \leq 1)$

Calculation the value from standard normal z table, we have,

$P(x > 90) = 1 - 0.8413 = 0.1587 = 15.87\%$

15.87% of children of class will require more than 90 minutes to complete the test.

Number of children =

$\dfrac{15.87}{100}\times 60 = 9.52\approx 10$

Approximately, 10 students of class will require more than 90 minutes to complete the test.

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3 years ago

Rachel's Coffee Shop makes a blend that is a mixture of two types of coffee. Type A coffee costs Rachel $4.30 per pound, and typ

Sergio039 [100]

Step 1

Write out the system of equations

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Step 2

Find the value of one pound of type A coffee, x

$\begin{gathered} From\text{ equation 2; x+y=148} \\ Therefore \\ y=148-x \end{gathered}$ $\begin{gathered} Substitute\text{ for y in equation 1} \\ 4.30x+5.9(148-x)=738.80 \\ 4.30x+873.2-5.9x=738.80 \\ 873.2-738.80=5.9x-4.3x \\ 134.4=1.6x \\ x=84pounds \end{gathered}$

Therefore the answer will be;

$\begin{gathered} x+y=148 \\ 84+y=148 \\ y=64\text{ pounds} \\ \end{gathered}$

The pounds of type B coffee she used is 64pounds

The pounds of type A coffee she used is 84 pounds

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1 year ago

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pav-90 [236]

180/135=133.33
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Hope this helps!

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3 years ago

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