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2 years ago

Plz help me asap i will mark you brainly

Mathematics

2 answers:

Andreas93 [3]2 years ago

8 0

Answer:

2 and a 1/2 hrs

Step-by-step explanation:

Maksim231197 [3]2 years ago

7 0

Answer:

2.5 hours

Step-by-step explanation:

Divide the travelled miles by the amount of hours to get the travelled miles for one hour. (17 miles in 1 hour) Then divide 42.5 by 17 to get the amount of time it takes to go 42.5 miles. (42.5 miles in 2.5 hours)

Hope this helps!

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The question in picture attached

krek1111 [17]

Need free pointtdsssss

4 0

2 years ago

1.2 ÷ 4 = 12 tenths ÷ 4

Harlamova29_29 [7]

Answer:

Yes you're right, it does

3 0

3 years ago

Calculate the sample mean and sample variance for the following frequency distribution of heart rates for a sample of American a

spin [16.1K]

Answer:

$Mean = 68.9$

$s^2 =18.1$ --- Variance

Step-by-step explanation:

Given

$\begin{array}{cccccc}{Class} & {51-58} & {59-66} & {67-74} & {75-82} & {83-90} \ \\ {Frequency} & {6} & {3} & {11} & {13} & {4} \ \end{array}$

Solving (a): Calculate the mean.

The given data is a grouped data. So, first we calculate the class midpoint (x)

For 51 - 58.

$x = \frac{1}{2}(51+58) = \frac{1}{2}(109) = 54.5$

For 59 - 66

$x = \frac{1}{2}(59+66) = \frac{1}{2}(125) = 62.5$

For 67 - 74

$x = \frac{1}{2}(67+74) = \frac{1}{2}(141) = 70.5$

For 75 - 82

$x = \frac{1}{2}(75+82) = \frac{1}{2}(157) = 78.5$

For 83 - 90

$x = \frac{1}{2}(83+90) = \frac{1}{2}(173) = 86.5$

So, the table becomes:

$\begin{array}{cccccc}{x} & {54.5} & {62.5} & {70.5} & {78.5} & {86.5} \ \\ {Frequency} & {6} & {3} & {11} & {13} & {4} \ \end{array}$

The mean is then calculated as:

$Mean = \frac{\sum fx}{\sum f}$

$Mean = \frac{54.5*4+62.5*3+70.5*11+78.5*13+86.5*4}{6+3+11+13+4}$

$Mean = \frac{2547.5}{37}$

$Mean = 68.9$ -- approximated

Solving (b): The sample variance:

This is calculated as:

$s^2 =\frac{\sum (x - \overline x)^2}{\sum f - 1}$

So, we have:

$s^2 =\frac{(54.5-68.9)^2+(62.5-68.9)^2+(70.5-68.9)^2+(78.5-68.9)^2+(86.5-68.9)^2}{37 - 1}$

$s^2 =\frac{652.8}{36}$

$s^2 =18.1$ -- approximated

5 0

2 years ago

Pls help asap! i will mark brainliest!

mina [271]

Answer:

Step-by-step explanation:

2 x 7= 14 - 17= 3

6 0

2 years ago

Write an equation in standard form that is parallel to the line y = 2x - 1 that passes through the point (1, 2). 2x - y = 0 O x

timofeeve [1]

Answer:

2x - y = 0

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

y = 2x - 1 ← is in slope- intercept form

with slope m = 2

Parallel lines have equal slopes, thus

y = 2x + c ← is the partial equation

To find c substitute (1, 2) into the partial equation

2 = 2 + c ⇒ c = 2 - 2 = 0

y = 2x ← equation in slope- intercept form

Subtract y from both sides

0 = 2x - y , that is

2x - y = 0 ← equation in standard form

5 0

3 years ago