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3 years ago

PLEASE HELP (WILL NAME BRAINLYEST)

Mathematics

1 answer:

ira [324]3 years ago

7 0

Answer:

4.04 x 10^0 people/km^2 (x 10^0 is fairly redundant but if the answer is required in standard form then include it)

Step-by-step explanation:

Population Density = Population/Area

= 3.11 x 10^7 / 7.69 x 10^6

= 31,100,000 / 7,690,000

= 3110 / 769

= 4.04

= 4.04 x 10^0

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A bookstore had 60 copies of a magazine. Yesterday, it sold 1/3 of them. Today, it sold 1/4 of what remained. How many copies do

lara [203]

Answer:

Step-by-step explanation:

1/3 of 60 is 20

40 would be left

1/4 of 40 is 10 so 30 would be left

7 0

3 years ago

Noah and Lin are marketing paper cones to hold popcorn to hand out at parent math night. They want the cones to hold 9 cubic inc

Vadim26 [7]

Answer: r = 1.69 inches

h = 2.15 inches

Step-by-step explanation: Volume of a solid is the amount of space contained within a solid.

Volume of a cone is directly proportional to radius and height:

$V=\frac{1}{3}\pi r^{2}h$

They want the cones to hold the same volume of 9 cubic inches.

If height is 3:

$9=\frac{1}{3}\pi r^{2}3$

$\pi r^{2}=9$

$r^{2}=2.864$

r = 1.69 inches

When height is 3, radius is 1.69 inches for a cone to have 9 cubic inches of volume.

If radius is 2:

$9=\frac{1}{3}\pi (2)^{2}h$

$h=\frac{9(3)}{4 \pi}$

h = 2.15 inches

If radius is 2 inches, height of the cone is 2.15 inches.

6 0

3 years ago

Find the sum of the first 18 terms of the arithmetic sequence whose nth term is an = 3n - 1.

vodka [1.7K]

Answer:

495

Step-by-step explanation:

In order to find the sum of the first 18 terms you have to find the 18th term and the first term using the equation given.

a1=3(1)-1 a1=2

a18=3(18)-1 a18= 53

Then plug in 53 for an, 18 for n, and 2 in for a1 in the sum equation: Sn=n/2(a1+an)

Sn=18/2(2+53) Solve for sn= 495

7 0

3 years ago

ANSWER ASAP!! WILL GIVE OR MORE POINTS TO THE FIRST ONE WHO ANSWERS!

Sergio [31]

Answer: See the picture attached.

Step-by-step explanation:

Given the following mixed numbers:

$-2\frac{3}{4}\\\\-4\frac{1}{2}$

You need to convert them to decimal numbers. The steps to do this are shown below:

1. Divide the numerator of the fraction by the denominator.

2. Add the quotient obtained to the whole number part.

Then:

$-2\frac{3}{4}=-(2+0.75)=-(2.75)=-2.75\\\\-4\frac{1}{2}=-(4+0.5)=-(4.5)=-4.5$

Therefore, the point is:

$(-2.75,-4.5)$

Where $-2.75$ is the x-coordinate and $-4.5$ is the y-coordinate.

Knowing this, you can plot it on the coordinate plane, as you can see in the picture attached.

8 0

2 years ago

Select an equation that is equivalent to a^2-144b^2 a) (a-12b)^2 B) (a+12b)^2 C) (a-12b)(a+12b) C) a^2-24ab+144b^2

Nataliya [291]

Answer:

C) (a-12b)(a+12b)

Step-by-step explanation:

a^2-144b^2 = (a-12b)(a+12b)

This is the formula that when two terms squared are written with a minus sign between them their factors are the product of the original numbers once with a plus sign and once with the minus sign.

This can be explained by multiplying them.

(a-12b)

*(a+12b)

a²- 12ab

+12ab - 144b²

a² +0 - 144b²

We see we get the same answer as applying the formula above.

4 0

2 years ago