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2 years ago

6

During a sale at the bookstore, books sold for $4 and magazines sold for $3.50. Jan spent $22 and bought a total of 6 books

and magazines. How many of each did she buy?

1 answer:

Vinvika [58]2 years ago

8 0

Answer:

four magazines and two books

Step-by-step explanation:

3.50*4= 14

4*2= 8

14+8= 22

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| 15. Write an equation and solve.

docker41 [41]

Answer:

The value x in the equation 50=14+x+7+2x-1 is 10

Step-by-step explanation:

Given that the length of one side of a triangle is 14 inches

Let a be the length of one side

Therefore a=14 inches

The length of second side in x+7 inches

Let b be the length of second side

b=x+7 inches.

The length of third side is 2x-1 inches

Let c be the length of third side

c=2x-1 inches

And perimeter of the triangle =50 inches

Perimeter of a triangle =a+b+c

Equation can be written as

50=14+x+7+2x-1

50=20+3x ( adding the like terms )

Rewritting as below

3x+20=50

3x+20-50=50-50

3x-30=0

3x-30+30=0+30

3x=30

$x=\frac{30}{3}$

Therefore x=10

The value of x is 10

4 0

2 years ago

Find the center of mass of the wire that lies along the curve r and has density =4(1 sin4tcos4t)

dolphi86 [110]

The mass of the wire is found to be 40π√2 units.

<h3>How to find the mass?</h3>

To calculate the mass of the wire which runs along the curve r ( t ) with the density function δ=5.

The general formula is,

Mass = $\int_a^b \delta\left|r^{\prime}(t)\right| d t$

To find, we must differentiate this same given curve r ( t ) with respect to t to estimate |r'(t)|.

The given integration limits in this case are a = 0, b = 2π.

Now, as per the question;

The equation of the curve is given as;

r(t) = (4cost)i + (4sint)j + 4tk

Now, differentiate this same given curve r ( t ) with respect to t.

$\begin{aligned}\left|r^{\prime}(t)\right| &=\sqrt{(-4 \sin t)^2+(4 \cos t)^2+4^2} \\&=\sqrt{16 \sin ^2 t+16 \cos ^2 t+16} \\&=\sqrt{16\left(\sin t^2+\cos ^2 t\right)+16}\end{aligned}$

Further simplifying;

$\begin{aligned}&=\sqrt{16(1)+16} \\&=\sqrt{16+16} \\&=\sqrt{32} \\\left|r^{\prime}(t)\right| &=4 \sqrt{2}\end{aligned}$

Now, use integration to find the mass of the wire;

$\begin{aligned}&=\int_a^b \delta\left|r^{\prime}(t)\right| d t \\&=\int_0^{2 \pi} 54 \sqrt{2} d t \\&=20 \sqrt{2} \int_0^{2 \pi} d t \\&=20 \sqrt{2}[t]_0^{2 \pi} \\&=20 \sqrt{2}[2 \pi-0] \\&=40 \pi \sqrt{2}\end{aligned}$

Therefore, the mass of the wire is estimated as 40π√2 units.

To know more about density function, here

brainly.com/question/27846146

#SPJ4

The complete question is-

Find the mass of the wire that lies along the curve r and has density δ.

r(t) = (4cost)i + (4sint)j + 4tk, 0≤t≤2π; δ=5

5 0

1 year ago

I'm doing test corrections rn but I need to show the work for this answer. The problem is that the this doesn't show the work an

BabaBlast [244]

The two angles are corresponding angles, so they are congruent (due to the horizontal lines being parallel)

x+15 = 102

x+15-15 = 102-15 .... subtract 15 from both sides

x = 87

6 0

2 years ago

The stem-and-leaf plot below gives the gas mileages (in miles per gallon) for 14 new cars. Use the plot to answer the questions

Sauron [17]

Answer:

a) 1

b) 58

c) 47

Step-by-step explanation:

don't really have a step by step explanation I just took the information from the chart and applied it to the questions

5 0

2 years ago

As a motivational speaker, Bree speaks at school assemblies, charging a school

Oksi-84 [34.3K]

Answer:

<em>Bree spoke at 55 assemblies in this district.</em>

Step-by-step explanation:

Bree speaks at school assemblies charging a school district a total cost C modeled by the equation:

C(a) = 50a+1,500

Being a the number of assemblies attending the meeting.

It's given Bree charged the Escambia City School District $4,250 to speak at school assemblies.

We can find the number of assemblies by solving the equation:

50a+1,500=4,250

Subtracting 1,500:

50a=4,250-1,500=2,750

Dividing by 50;

a = 2,750 / 50=55

Bree spoke at 55 assemblies in this district.

4 0

2 years ago