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3 years ago

Find the sum of the arithmetic series given ai = 45, an = 85, and n = 5.

Mathematics

1 answer:

seraphim [82]3 years ago

5 0

Answer:

C. 325.

Step-by-step explanation:

The last term a5 = 85

a1 = 45

Sum of n terms = n/2 (a1 + l)

So here we have n = 5, a1 = 45 and the last term l = 85

= (5/2)(45 + 85)

= 5/2 * 130

= 325.

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A recent national survey found that high school students watched an average (mean) of 6.8 movies per month with a population sta

Margaret [11]

Answer:

Step-by-step explanation:

Given that x = no of movies high school students watched is N(6.8, 1.8)

Sample size = 36 and hence std error = 1.8/6 = 0.3

$H_0: x bar = 6.8\\H_a: x bar < 6.8\\$

(two tailed test)

Mean difference = 6.2-6.8 = -0.6

Test statistic z = -0.6/0.3= -2

p value = 0.02275

Since p <0.05 we reject H0.

There is evidence to show that college students watch fewer movies a month than high school students

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3 years ago

ujalakhan01 can you answer these? 1. In Spencer’s garden, the number of rose bushes is 7 less than 1.5 times the number of carna

aniked [119]

Answer:

42.05x + 50.36

Step-by-step explanation:

1. It is 1.5c - 7 because tje mumber of rose bushes is 7 less that 1.5(c), not 1.5(7). So, it is (b).

2. 9.78(4.3x + 5.15)

42.05x + 50.36

Hope this helps:)

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7 0

3 years ago

Find 3 consecutive even integers if their sum decreased by 10 equals -22

Orlov [11]

Three consecutive even integers can be represented by x, (x+2), and (x+4).

(x + (x + 2) + (x + 4)) - 10 = -22 Get rid of the parentheses
x + x + 2 + x + 4 - 10 = -22 Combine like terms (x + x + x) and (2 + 4 - 10)
3x - 4 = -22 Add 4 to both sides
3x = -18 Divide
x = -6
Check you work.

x = -6
x + 2 = -4
x + 4 = -2

(-6 - 4 - 2) - 10 = 22
-12 - 10 = -22

So, your three integers are -6, -4, and -2 .

6 0

4 years ago

Starting at the same point at the same time, Samuel and Heather rode their bikes in the same direction. Samuel traveled 3km/h fa

12345 [234]

Samuel was going with 40 km/h and Heather was going with 37 km/h

Step-by-step explanation:

Starting at the same point at the same time, Samuel and Heather rode their bikes in the same direction

Samuel traveled 3 km/h faster than Heather
After 3.5 h Samuel stopped for a half-hour break, but Heather kept going
Heather was 8 km ahead of Samuel

We need to find how fast each was going

Assume that Heather's speed is x km/h

∵ Heather's speed = x km/h

∵ Samuel traveled 3 km/h faster than Heather

∴ Samuel's speed = x + 3 km/h

The formula of the distance is distance = speed × time

∵ Samuel travel for 3.5 hours

- Find the distance that Samuel traveled in 3.5 h

∴ Samuel distance = (x + 3) × 3.5

- Multiply the bracket by 3.5 to simplify

∴ Samuel distance = 3.5x + 10.5

∵ Samuel took a break for half hour

∵ Heather kept going

∵ At the end of the break, Heather was 8 km ahead of Samuel

- That means Heather was going for 4 hours (3.5 + 0.5), and her

distance is longer than Samuel distance by 8 km

∴ Heather distance = x × 4 = 4x

- Subtract the distance of Samuel from the distance of Heather

and equate the difference by 8

∵ 4x - (3x + 10.5) = 8

∴ 4x - 3x - 10.5 = 8

- Add the like terms in the left hand side

∴ 0.5x - 10.5 = 8

- Add 10.5 to both sides

∴ 0.5x = 18.5

- Divide both sides by 0.5

∴ x = 37

∵ x represents Heather's speed

∴ Heather's speed = 37 km/h

∵ x + 3 represents Samuel's speed

∴ Samuel's speed = 37 + 3 = 40 km/h

Samuel was going with 40 km/h and Heather was going with 37 km/h

Learn more:

You can learn more about the equation of motion in brainly.com/question/568302

#LearnwithBrainly

3 0

4 years ago

The senior class want to play a practical joke on the principal, who was a former college basketball star. They want to fill his

steposvetlana [31]

The number of basketball that will fill up the entire office is approximately 16,615.

Recall:

Volume of a spherical shape = $\frac{4}{3} \pi r^3$

Volume of a rectangular prism = $l \times w \times h$

Given:

Diameter of basketball = 9.5 in.

Radius of the ball = 1/2 of 9.5 = 4.75 in.

Radius of the ball in ft = 0.4 ft (12 inches = 1 ft)

Dimension of the office (rectangular prism) = 20 ft by 18 ft by 12 ft

First, find the volume of the basketball:

Volume of ball = $\frac{4}{3} \pi r^3 = \frac{4}{3} \times \pi \times 4.75^3\\$

Volume of basketball = $448.92 $ in^3$

Convert to $ft^3$

$1728 $ in.^3 = 1 $ ft^3$

Therefore,

Volume of basketball = $\frac{448.92}{1728} = 0.26 $ ft^3$

Find the volume of the office (rectangular prism):

Volume of the office = $20 \times 18 \times 12 = 4,320 $ ft^3$

Number of basket ball that will fill the office = Volume of office / volume of basketball

Thus:

Number of basket ball that will fill the office = $\frac{4,320}{0.26} = 16,615$

Therefore, it will take approximately 16,615 balls to fill up the entire office.

Learn more here:

brainly.com/question/16098833

6 0

3 years ago