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2 years ago

If you have a stack of pennies without counting them how do you know if there is an even or odd number of them

Mathematics

1 answer:

zavuch27 [327]2 years ago

5 0

If I have a stack of pennies. And I have to tell that without counting whether there are even number of pennies or odd.

Even numbers are the numbers which are divisible by 2 and odd numbers are the numbers which are not divisible by 2.

Then I will put the given pennies in 2 rows and then I will match them to form a pair of 2 pennies. After matching, if there is 1 penny left over, then there is an odd number of pennies and if all the pennies have a match,then there is an even number of pennies.

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What is the difference? StartFraction 2 x + 5 Over x squared minus 3 x EndFraction minus StartFraction 3 x + 5 Over x cubed minu

lisov135 [29]

Answer:

A. StartFraction (x + 5) (x + 2) Over x cubed minus 9 x EndFraction

Step-by-step explanation:

Given:

(2x + 5) / (x² - 3x) - (3x + 5) / (x³ - 9x) - (x + 1) / x² - 9

Factor the denominators

(2x + 5) / x(x - 3) - (3x + 5) / x(x - 3)(x + 3) - (x + 1) / (x - 3)(x + 3)

Lowest common multiple of the 3 fractions is x(x - 3)(x + 3)

= (2x+5)(x+3) - (3x + 5) - (x + 1)x / x(x - 3)(x + 3)

= (2x²+6x+5x+15) - (3x + 5) - (x² + x) / x(x - 3)(x + 3)

= 2x² + 11x + 15 - 3x - 5 - x² - x / x(x - 3)(x + 3)

= x² + 7x + 10 / x(x - 3)(x + 3)

Solve the numerator.

Solve the quadratic expression by finding two numbers whose product is 10 and sum is 7

The numbers are 5 and 2

= x² + 5x + 2x + 10 / x(x - 3)(x + 3)

= x(x + 5) + 2(x + 5) / x(x - 3)(x + 3)

= (x + 5)(x + 2) / x(x - 3)(x + 3)

A. StartFraction (x + 5) (x + 2) Over x cubed minus 9 x EndFraction

Recall,

x(x - 3)(x + 3) is a factor of x³ - 8x

A. StartFraction (x + 5) (x + 2) Over x cubed minus 9 x EndFraction

(x + 5)(x + 2) / x³ - 9x

B. StartFraction (x + 5) (x + 4) Over x cubed minus 9 x EndFraction

(x + 5)(x + 4) / x³ - 9x

C. StartFraction negative 2 x + 11 Over x cubed minus 12 x minus 9 EndFraction

2x + 11 / x³ - 12x - 9

D. StartFraction 3 (x + 2) Over x squared minus 3 x EndFraction

3(x + 2) / x² - 3x

3 0

1 year ago

Miriam reduced a square photo by cutting 3 inches away from the length and the width so it will fit in her photo album. The area

Rina8888 [55]

Answer:

11 inches by 11 inches

Step-by-step explanation:

The dimensions of the original photo were 11 inches by 11 inches.

We are informed that the area of the reduced photo is 64 square inches and that In the equation (x – 3)^2 = 64, x represents the side measure of the original photo.

In order to solve for x, we shall first take square roots on both sides of the equation;

The square root of (x – 3)^2 is simply (x - 3).

The square root of 64 is ±8 but we ignore -8 since the dimensions of any figure must be positive.

Therefore, we have the following equation;

x - 3 = 8

x = 8 + 3

x = 11

3 0

2 years ago

Read 2 more answers

Match each concept with its key characteristic.

Crank

1. It is the subset of a group - Group sample.

2. It equally favors all members of a group sample - Random sample.

3. It collects data on members of a group - Survey.

4. It does not equally favor all members of a group - Biased sample.

5. It includes all members of a group - Population.

6. It analyzes data collected from a group - Mean.

I have matched all concepts in accordance with statistical use, hope it helps.

6 0

2 years ago

If a cube-shaped cell is 3 units tall by 3 units wide and 3 units long, what is the cell's surface-area-to volume ratio?

bulgar [2K]

The cube has 6 sides, each a square with dimensions 3 by 3,

the area of any of these squares is 3*3=9 square units.

The total area of the cube is 6*9 square units=54 square units

The volume of a cube with side length a is given by : $\displaystyle{ V_{cube}=a^3$ , thus the volume of the cube-shaped cell is 3*3*3=27 cube units.

(surface area):(volume)=54:27 = 2:1 =2

Answer:

the ratio of the numerical values is 2

(their ratio including units is 2/unit

7 0

2 years ago

The length of time a full length movie runs from opening to credits is normally distributed with a mean of 1.9 hours and standar

Llana [10]

Answer:

a) The probability that a random movie is between 1.8 and 2.0 hours = 0.2586.

b) The probability that a random movie is longer than 2.3 hours is 0.0918.

c) The length of movie that is shorter than 94% of the movies is 1.4 hours

Step-by-step explanation:

In the above question, we would solve it using z score formula

z = (x-μ)/σ, where x is the raw score, μ is the population mean, and σ is the population standard deviation

a) A random movie is between 1.8 and 2.0 hours

z = (x-μ)/σ,

x1 = 1.8,

x2 = 2.0

μ is the population mean = 1.9

σ is the population standard deviation = 0.3

z1 = (1.8 - 1.9)/0.3

z1 = -1/0.3

z1 = -0.33333

Using the z score table

P(z1 = -0.33) = 0.3707

z2 = (2.0 - 1.9)/0.3

z1 = 1/0.3

z1 = 0.33333

p(z2 = 0.33) = 0.6293

= P(- 0.33 ≤ z ≤ 0.33)

= 0.6293 - 0.3707

= 0.2586

The probability that a random movie is between 1.8 and 2.0 hours = 0.2586

b) A movie is longer than 2.3 hours

z = (x-μ)/σ,

x1 = 2.3

μ is the population mean = 1.9

σ is the population standard deviation = 0.3

z = (2.3 - 1.9)/0.3

z = 4/0.3

z = 1.33333

P(z = 1.33) = 0.90824

P(x>2.3) = = 1 - 0.90824

= 0.091759

≈ 0.0918

The probability that a random movie is longer than 2.3 hours is 0.0918.

3) The length of movie that is shorter than 94% of the movies.

z = (x-μ)/σ

Probability (z ) = 94% = 0.94

Movie that is shorter than 0.94

= P(1 - 0.94) = P(0.06)

Finding the P (x< 0.06) = -1.555

≈ -1.56

μ is the population mean = 1.9

σ is the population standard deviation = 0.3

-1.56 = (x - 1.9)/ 0.3

Cross multiply

-1.56 × 0.3 = x - 1.9

- 0.468 + 1.9 = x

= 1.432 hours

≈ 1.4 hours

Therefore, the length of movie that is shorter than 94% of the movies is 1.4 hours

5 0

1 year ago