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3 years ago

10

Nick O’ Time, the plumber, charges $30 per hour. His brother Ivan, the plumber’s helper, charges $20 per hour. Nick starts worki

ng on a job. Four hours later Ivan joins him and both work until the job is finished. If they make a total of $470, how long did they work together?

1 answer:

lianna [129]3 years ago

8 0

Answer:

7 hours

They worked together for 7 hours ($350 + $120)

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Kari is flying a kite. She releases 50 feet of string. What is the approximate difference in the height of the kite when the str

MakcuM [25]

Answer:

Step-by-step explanation:

The string of a kite forms a right angle triangle with the ground. The length of the string represents the hypotenuse of the right angle triangle. The height of the kite represents the opposite side of the right angle triangle.

To determine the height of the kite, we would apply the sine trigonometric ratio which is expressed as

Sin θ = opposite side/hypotenuse.

1) if the kite makes an angle of 25° with the ground, then the height, h would be

Sin 25 = h/50

h = 50Sin25 = 50 × 0.4226

h = 21.1 feet

2) if the kite makes an angle of 45° with the ground, then the height, h would be

Sin 45 = h/50

h = 50Sin45 = 50 × 0.7071

h = 35.4 feet

The approximate difference in the height of the kite is

35.4 - 21.1 = 14.3 feet

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3 years ago

Choose an algebraic expression for: 9 more than w

denis-greek [22]

The answer is a.w+9 because it means the w plus 9 more it the same as 9 more than w

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3 years ago

Is this enough to see

Oksana_A [137]

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3 years ago

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Please consider the following values for the variables X and Y. Treat each row as a pair of scores for the variables X and Y (wi

Studentka2010 [4]

Answer:

The Pearson's coefficient of correlation between the is 0.700.

Step-by-step explanation:

The correlation coefficient is a statistical degree that computes the strength of the linear relationship amid the relative movements of the two variables (i.e. dependent and independent).It ranges from -1 to +1.

The formula to compute correlation between two variables <em>X</em> and <em>Y</em> is:

$r(X, Y)=\frac{Cov(X, Y)}{\sqrt{V(X)\cdot V(Y)}}$

The formula to compute covariance is:

$Cov(X, Y)=n\cdot \sum XY-\sum X \cdot\sum Y$

The formula to compute the variances are:

$V(X)=n\cdot\sum X^{2}-(\sum X)^{2}\\V(Y)=n\cdot\sum Y^{2}-(\sum Y)^{2}$

Consider the table attached below.

Compute the covariance as follows:

$Cov(X, Y)=n\cdot \sum XY-\sum X \cdot\sum Y$

$=(5\times 165)-(30\times 25)\\=75$

Thus, the covariance is 75.

Compute the variance of X and Y as follows:

$V(X)=n\cdot\sum X^{2}-(\sum X)^{2}\\=(5\times 226)-(30)^{2}\\=230\\\\V(Y)=n\cdot\sum Y^{2}-(\sum Y)^{2}\\=(5\times 135)-(25)^{2}\\=50$

Compute the correlation coefficient as follows:

$r(X, Y)=\frac{Cov(X, Y)}{\sqrt{V(X)\cdot V(Y)}}$

$=\frac{75}{\sqrt{230\times 50}}$

$=0.69937\\\approx0.70$

Thus, the Pearson's coefficient of correlation between the is 0.700.

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3 years ago

What is the value of x? x = 23 x = 35 x = 58 x = 93

Akimi4 [234]

we know that

m∠SQR+x= $180$ -------> by supplementary angles

so

m∠SQR= $180-x$

The sum of the internal angles of a triangle is equal to $180$ degrees

m∠SQR+m∠QSR+m∠SRQ= $180$

substitute the values in the formula

m∠SQR+ $35$ + $58$ = $180$

m∠SQR= $87$ degrees

<u>Find the value of x</u>

m∠SQR= $180-x$

x= $180$ -m∠SQR

x= $180-87$

x= $93$ degrees

therefore

<u>the answer is</u>

the value of x is $93$ degrees

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2 years ago

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