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3 years ago

15

the relative frequency that the traffic lights will show RED at road works is 0.2. Estimate how many times they will show RED ov

er the next 40 journeys.

2 answers:

tensa zangetsu [6.8K]3 years ago

8 0

Only 8 times because you take .2 times 40

adell [148]3 years ago

7 0

Yes you multiply 40*0.2 and that would be 8.

You might be interested in

Usimov [2.4K]

Answer:

Yes, 19.3649167 < 20

Step-by-step explanation:

Do the Pythagorean theorem to figure out the height.

35^2 + x^2 = 40^2

1225 + x^2 = 1600

x^2 = 375

x = 19.3649167

7 0

3 years ago

The face of the triangular concrete panel shown has an area of 22 square meters, and its base is 3 meters longer than twice its

Elodia [21]

Answer:

The length of the base is 11 meters.

Step-by-step explanation:

The diagram of the triangle is not shown; However, the given details are enough to solve this question.

Given

<em>Shape: Triangle</em>

<em>Represent the height with h and the base with b</em>

$b = 3 + 2h$

$Area = 22$

Required

Find the length of the base

The area of a triangle is calculated as thus;

$Area = \frac{1}{2} * b * h$

Substitute 22 for Area and 3 + 2h for b

The formula becomes

$22 = \frac{1}{2} * (3 + 2h) * h$

Multiply both sides by 2

$2 * 22 = 2 * \frac{1}{2} * (3 + 2h) * h$

$44 = (3 + 2h) * h$

Open the bracket

$44 = 3 * h + 2h * h$

$44 = 3h + 2h^2$

Subtract 44 from both sides

$44 - 44 = 3h + 2h^2 - 44$

$0 = 3h + 2h^2 - 44$

Rearrange

$0 = 2h^2 +3h - 44$

$2h^2 +3h - 44 = 0$

At this point, we have a quadratic equation; which is solved as follows:

$2h^2 +3h - 44 = 0$

$2h^2 + 11h - 8h - 44 = 0$

$h(2h + 11) - 4(2h + 11) = 0$

$(h - 4)(2h + 11) = 0$

Split the above

$(h - 4) = 0\ or\ (2h + 11) = 0$

$h - 4 = 0\ or\ 2h + 11 = 0$

Solve the above linear equations separately

$h - 4 = 0$

Add 4 to both sides

$h - 4 + 4 = 0 + 4$

$h = 0 + 4$

$h = 4$ ---- <em>First value of h</em>

$2h + 11 = 0$

Subtract 11 from both sides

$2h + 11 - 11 = 0 - 11$

$2h = 0 - 11$

$2h = -11$

Divide both sides by 2

$\frac{2h}{2} = -\frac{11}{2}$

$h = -\frac{11}{2}$ <em> ------ Second value of h</em>

Since height can be negative, we'll discard $h = -\frac{11}{2}$

Hence, the usable value of height is $h = 4$

Recall that $b = 3 + 2h$

Substitute 4 for h

$b = 3 + 2(4)$

$b = 3 + 8$

$b = 11$

Hence, the length of the base is 11 meters

3 0

3 years ago

Factor completly x^8- 1/81. please help:)

Leno4ka [110]

Answer:

${x}^{8} - \frac{1}{81} = ( {x}^{4} + \frac{1}{9} )( {x}^{2} + \frac{1}{3} )(x + \frac{1}{ \sqrt{3} } )(x - \frac{1}{ \sqrt{3} } )$

Step-by-step explanation:

see the picture attached for further explanation.

5 0

3 years ago

Read 2 more answers

which items of information are necessary to calculate the mass percent of an element in a given compound? select all that apply.

solmaris [256]

The mass percent of an element in a compound can be calculated by knowing specific items of information

The items of information necessary are;

The molar mass of the element, $MM_{element }$

The count of the number of moles of the element in the compound, <em>n</em>

The compound's formula

The compound's molar mass

Reasons:

The mass percent of an element in a compound is given as follows;

$Mass \ percent \ of \ element \ in \ a \ compound = \dfrac{MM_{element } \times n}{MM_{compound}} \times 100$

Where;

$MM_{element }$ = Molar mass of the element

$MM_{compound}$ = Molar mass of the compound

n = The number of moles of the element in the compound

Therefore, the items of information necessary to calculate the mass percent in a given compound are;

The molar mass of the element, $MM_{element }$

$MM_{element }$ , gives the mass per unit of the element in the compound

The count of the number of moles of the element in the compound, <em>n</em>

The number of moles of the element per mole of the compound gives the number by which the molar mass is multiplied, to get the mass of the element in the compound

The compound's formula

The formula of the compound is the source of information of the number of moles of the element present in a mole of the compound

The compound's molar mass

The molar mass of the compound is the mass to which the mass of the element in a mole of the compound is a fraction. That is the mass that divides the mass of the element in the calculation of the mass percent of the element

With the above information about the element in the compound, its mass percent can be calculated

Learn more here:

brainly.com/question/13648441

4 0

2 years ago

HELPPP !!! ILL MARL BRAINLIST

almond37 [142]

Answer:

Hi there!

Your answers are:

1) 2^4 = 2×2×2×2 = 16

2) 2^3= 2×2×2= 8

3) 2^2 = 2×2 = 4

4) 2^1 = 2

5)2^0 = 1

6)2^ -1 = .5

7) 2^ -2 = .25

8) 2^ -3 = .125

9) 2^ -4= .0625

Hope this helps

3 0

3 years ago