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3 years ago

PLEASE HELP ASAP!!!!

Mathematics

2 answers:

ASHA 777 [7]3 years ago

7 0

Answer:

(8+24)÷(12x4) the correct answer is B

Mamont248 [21]3 years ago

3 0

Answer:

b i think so hope my thinking is right

Step-by-step explanation:

You might be interested in

A square building with an area of 225 m2 has a garden surrounding it that has an equal width on all sides. The area of the garde

xenn [34]

Answer:

The width of the garden is 1.16 m

Step-by-step explanation:

step 1

<em>Find the area of the garden</em>

To find out the area of the garden multiply by 1/3 the area of the building

$225(\frac{1}{3})=75\ m^2$

step 2

Find the length side of the square building

The area of a square is

$A=b^2$

where

b is the length side of the square

we have

$A=225\ m^2$

$b^2=225\\b=15\ m$

step 3

Find the width of the garden

Let

x ----> the width of the garden

we know that

The area of the building plus the area of the garden is equal to

$(15+2x)^2=225+75$

solve for x

$225+60x+4x^2=225+75\\4x^2+60x-75=0$

Solve the quadratic equation by graphing

using a graphing tool

The solution is x=1.16 m

see the attached figure

therefore

The width of the garden is 1.16 m

Find the exact value

The formula to solve a quadratic equation of the form $ax^{2} +bx+c=0$

is equal to

$x=\frac{-b\pm\sqrt{b^{2}-4ac}} {2a}$

in this problem we have

$4x^2+60x-75=0$

$a=4\\b=60\\c=-75$

substitute in the formula

$x=\frac{-60\pm\sqrt{60^{2}-4(4)(-75)}} {2(4)}$

$x=\frac{-60\pm\sqrt{4,800}} {8}$

$x=\frac{-60\pm40\sqrt{3}} {8}$

$x=\frac{-60+40\sqrt{3}} {8}\ m$ ----> exact value

8 0

3 years ago

Is the percent increase from 50 to 70 equal to the percent decrease from 70 to 50? Explain.

PIT_PIT [208]

Answer:

No. The amounts of change are the same, but the original amounts are different.

6 0

3 years ago

Read 2 more answers

Which kind of figurative language is used throughout this excerpt?

lidiya [134]

Can you please show us the excerpt? :)

4 0

3 years ago

Read 2 more answers

In the Salk vaccine field trial, 400,000 children were part of a randomized controlled double-blind experiment. Just about half

EastWind [94]

Answer:

Step-by-step explanation:

From the given information:

The number of children that were randomly allocated to each vaccination group; n₁ = 200,000

No of polio cases X₁ = 57

Now, in the vaccine group:

the proportion of polio cases is:

$\hat p_1 = \dfrac{57}{200000}$

= 0.000285

The number of children that were randomly allocated to the placebo group, n₂ = 200,000

No of polio cases X₂ = 142

In the placebo group

the proportion of polio cases is:

$\hat p_2 = \dfrac{142}{200000}$

Null and alternative hypothesis is computed as follows:

H₀: There is no difference in the proportions of polio cases between both groups.

H₁: There is a difference in the proportions of polio cases between both groups.

Let assume that the level of significance ∝ = 0.05

The test statistic can be computed as:

$Z = \dfrac{\hat p_1-\hat p_2}{\sqrt{\dfrac{\hat p_1 \hat q_1}{n_1}+ \dfrac{\hat p_2 \hat q_2}{n_2}}}$

$Z = \dfrac{0.000285-0.000710}{\sqrt{\dfrac{0.000285(1-0.000285)}{200000}+ \dfrac{0.000710(1-0.000710)}{200000}}}$

$Z = \dfrac{-4.25\times 10^{-4}}{\sqrt{\dfrac{0.000285(0.999715)}{200000}+ \dfrac{0.000710(0.99929)}{200000}}}$

Z = - 6.03

P-value = 2P(Z < -6.03)

From the Z - tables

P-value = 2 × 0.0000

= 0.000

We reject the H₀ provided that P-value is very less.

Therefore, we may conclude that there is a difference in the proportions of polio cases between the vaccine group and placebo group not due to chance.

7 0

3 years ago

Interest centers around the life of an electronic component. Let A be the event that the component fails a particular test and B

nekit [7.7K]

Answer: a. 0.61

b. 0.37

c. 0.63

Step-by-step explanation:

From the question,

P(A) = 0.39 and P(B) = 0.24

P(success) + P( failure) = 1

A) What is the probability that the component does not fail the test?

Since A is the event that the component fails a particular test, the probability that the component does not fail the test will be P(success). This will be:

= 1 - P(A)

= 1 - 0.39

= 0.61

B) What is the probability that a component works perfectly well (i.e., neither displays strain nor fails the test)?

This will be the probability that the component does not fail the test minus the event that the component displays strain but does not actually fail. This will be:

= [1 - P(A)] - P(B)

= 0.61 - 0.24

= 0.37

C) What is the probability that the component either fails or shows strain in the test?

This will simply be:

= 1 - P(probability that a component works perfectly well)

= 1 - 0.37

= 0.63

3 0

3 years ago