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2 years ago

9

Gillian purchased 25 books at the library book sale. Each hardcover book cost $1.50, and each paperback book cost $0.50. Gillian

spent a total of $26.50. The book costs can be represented by the system of equations below.
h + p = 25
1.50h + 0.50p = 26.50

How many paperback books did Gillian buy?
11
12
13
14

2 answers:

pantera1 [17]2 years ago

7 0

Answer:

A on E2020

Step-by-step explanation:

Just did the test on Edge 2020

aev [14]2 years ago

3 0

Answer: The answer is 11 (A)

Step-by-step explanation:

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Gavin likes biking. He never misses a chance to go for a ride when the weather is nice. This week his goal is to bike about 65 t

andreyandreev [35.5K]

Answer:

How far should he ride on each of the four days to reach his goal?

1st day: $8$ miles

2nd day: $12$ miles

3rd day: $18$ miles

4th day: $27$ miles

Step-by-step explanation: As the problem says, $x$ is the number of miles he rides on the first day. Let's start off with that.

1st day: $x$ miles

He want to ride 1.5 times as far as he rode the day before... no 1.5 more, but 1.5 <em>times</em> as far as he rode the day before; you would multiply 1.5 with the previous day's length.

2nd day: $1.5x$

Then you multiply $1.5$ to $1.5x$ to get the third day's.

3rd day: $2.25x$

4th day: $3.375x$

----------------------------

Phew! Gavin wants to ride a total of 65 miles over these four days, so if Gavin added all the miles of the four days, he should get 65...

1st+2nd+3rd+4th=65

$x+1.5x+2.25x+3.375x=65$

$8.125x=65$

$\frac{8.125x}{8.125}=\frac{65}{8.125}$

$x=8$

Yes! Now that we've got the hard part done... substitute 8 for ever single $x$ .

1st day: $8$ miles

2nd day: $1.5(8)=12$ miles

3rd day: $2.25(8)=18$ miles

4th day: $3.375(8)=27$ miles

-------------------------

Checking my answer:

Just add the miles!

$8+12+18+27=65$

$65=65$

✓

-----------------------

Hope that helps! :D

5 0

2 years ago

A media personality argues that global temperatures are not rising, because every year an increase is reported such as 0.08 degr

marta [7]

Answer: C

Step-by-step explanation:

8 0

2 years ago

Three erasers and five pencils cost $7.55. 6 erasers and 12 pencils cost $17.40. How much does 1 eraser cost? How much does 1 pe

Sphinxa [80]

Answer:

Step-by-step explanation:

erasers=e

pencils=p

3e+5p=7.55 ...(1)

6e+12p=17.40

divide by 2

3e+6p=8.70 ...(2)

(2)-(1) gives

p=8.70-7.55=1.15

from (1)

3e+5(1.15)=7.55

3e+5.75=7.55

3e=7.55-5.75

3e=1.80

e=1.80/3=0.60

cost of 1 eraser=$0.60

cost of 1 pencil =$1.15

7 0

2 years ago

Evaluate the line integral by the two following methods. xy dx + x2y3 dy C is counterclockwise around the triangle with vertices

nadezda [96]

Answer:

a)

$\frac{2}{3}$

b)

$\frac{2}{3}$

Step-by-step explanation:

a) The first part requires that we use line integral to evaluate directly.

The line integral is

$\int_C xydx + {x}^{2} {y}^{3} dy$

where C is counterclockwise around the triangle with vertices (0, 0), (1, 0), and (1, 2)

The boundary of integration is shown in the attachment.

Our first line integral is

$L_1 = \int_ {(0,0)}^{(1,0)} xydx + {x}^{2} {y}^{3} dy$

The equation of this line is y=0, x varies from 0 to 1.

When we substitute y=0 every becomes zero.

$\therefore \: L_1 =0$

Our second line integral is

$L_2 = \int_ {(1,0)}^{(1,2)} xydx + {x}^{2} {y}^{3} dy$

The equation of this line is:

$x = 0 \implies \: dx = 0$

y varies from 1 to 2.

We substitute the boundary and the values to get:

$L_2 = \int_ {1}^{2}1 \cdot y(0) + {1}^{2} \cdot \: {y}^{3} dy$

$L_2 = \int_ {1}^2 {y}^{3} dy = \frac{8}{3}$

The 3rd line integral is:

$L_3 = \int_ {(1,2)}^{(0,0)} xydx + {x}^{2} {y}^{3} dy$

The equation of this line is

$y = 2x \implies \: dy = 2dx$

x varies from 0 to 1.

We substitute to get:

$L_3 = \int_ {1}^{0} x \cdot \: 2xdx + {x}^{2} {(2x)}^{3}(2 dx)$

$L_3 = \int_ {1}^{0} 8 {x}^{5} + 2 {x}^{2} dx = - 2$

The value of the line integral is

$L = L_1 + L_2 + L_3$

$L = 0 + \frac{8}{3} + - 2 = \frac{2}{3}$

b) The second part requires the use of Green's Theorem to evaluate:

$\int_C xydx + {x}^{2} {y}^{3} dy$

Since C is a closed curve with counterclockwise orientation, we can apply the Green's Theorem.

This is given by:

$\int_C \: Pdx +Q \: dy = \int \int_ R \: Q_y - P_x \: dA$

$\int_C \: xydx + {x}^{2} {y}^{3} \: dy = \int \int_ R \: 3 {x}^{2} {y}^{2} - y \: dA$

We choose our region of integration parallel to the y-axis.

$\int_C \: xydx + {x}^{2} {y}^{3} \: dy = \int_ 0^{1} \int_ 0^{2x} \: 3 {x}^{2} {y}^{2} - y \: dydx$

$\int_C \: xydx + {x}^{2} {y}^{3} \: dy = \int_ 0^{1} \: {x}^{2} {y}^{3} - \frac{1}{2} {y}^{2} |_ 0^{2x} dx$

$\int_C \: xydx + {x}^{2} {y}^{3} \: dy = \int_ 0^{1} \: 8{x}^{5} - 2 {x}^{2} dx = \frac{2}{3}$

8 0

2 years ago

Identify the focus, directrix, and axis of symmetry of the parabola 6x2+3y=0

Damm [24]

Manipulate the equation to get it in one of the following forms:
$x^{2} = 4py$ or $y^2=4px$

Subtract 3y from both sides of the equation: $6 x^{2} =-3y$
Divide by 6 on both sides of the equation (reduce): $x^{2} =- \frac{1}{2}y$
This is a parabola that opens down and the value of p = $- \frac{1}{8}$ .
The vertex is at the origin (0, 0)
Focus: (0, 0 + p) ⇒ $(0, - \frac{1}{8} )$
Directrix: y = 0 - p ⇒ $y = \frac{1}{8}$
Axis of Symmetry: x = 0

5 0

2 years ago