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Alekssandra [29.7K]

2 years ago

12

Skylar's grades on four math tests are 85, 78, 77, and 69. What does Skylar need to score on the next test in order to have a me

an score of 80?

1 answer:

olga_2 [115]2 years ago

6 0

She needs to score a 91 on her next test because 85+78+77+69+91=400 and 400 divided by 5 gives you a mean of 80.

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9. Your mathematics instructor claims that, over the years, 88% of his students have said that math is their favorite class. In

Tatiana [17]

Answer:

Step-by-step explanation:

For the null hypothesis,

H0: p = 88

For the alternative hypothesis,

Ha: p < 88

Considering the population proportion, probability of success, p = 0.88

q = probability of failure = 1 - p

q = 1 - 0.88 = 0.12

Considering the sample,

Sample proportion, P = x/n

Where

x = number of success = 21

n = number of samples = 32

P = 21/32 = 0.66

We would determine the test statistic which is the z score

z = (P - p)/√pq/n

z = (0.66 - 0.88)/√(0.88 × 0.12)/32 = - 3.83

The corresponding p value would be determined by looking at the normal distribution table for the area below the z score. Therefore,

P value = 0.00006

8 0

3 years ago

What is the 8th term of the geometric sequence a2 = 20 and r = 5

algol [13]

Answer:

8th term of geometric sequence is 312500

Step-by-step explanation:

Given : $a_2=20$ and common ratio (r) = 5

We have to find the 8th term of the geometric sequence whose $a_2=20$ and common ratio (r) = 5

Geometric sequence is a sequence of numbers in which next term is found by multiplying by a constant called the common ratio (r).

$a_n=ar^{n-1}$ ......(1)

where $a_n$ is nth term and a is first term.

For given sequence

a can be find using $a_2=20$ and r = 5

Substitute in (1) , we get,

$a_2=ar^{2-1}$

$\Rightarrow 20=a(5)$

$\Rightarrow a=4$

Thus, 8th term of the sequence denoted as $a_8$

Substitute n= 8 in (1) , we get,

$a_8=ar^{8-1} \\\\a_8=(4)r_{7} \\\\a_8=4(5)^7=4 \times 78125=312500$

Thus 8th term of geometric sequence is 312500

8 0

3 years ago

To simplify the expression 3+5×3-8÷4

oee [108]

Answer:

5x3

Step-by-step explanation:

this is the first step

5 0

3 years ago

You earn $8 per hour for babysitting plus $0.75 per mile that she has to drive . Write an equation to represent this situation a

Hoochie [10]

Answer:

8x+$0.75x.

Step-by-step explanation:

8x is the hours you babysit and $0.75x the miles you drive.

3 0

2 years ago

Read 2 more answers

What is the sum of 20x^2-10x-30

ivann1987 [24]

Answer:

The sum of the roots is 0.5

Step-by-step explanation:

<u><em>The correct question is</em></u>

What is the sum of the roots of 20x^2-10x-30

we know that

In a quadratic equation of the form

$ax^{2} +bx+c=0$

The sum of the roots is equal to

$-\frac{b} {a}$

in this problem we have

$20x^{2} -10x-30=0$

so

$a=20\\b=-10\\c=-30$

substitute

$-\frac{(-10)} {20}=0.5$

<u><em>Verify</em></u>

Find the roots of the quadratic equation

The formula to solve a quadratic equation is equal to

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

$a=20\\b=-10\\c=-30$

substitute

$x=\frac{-(-10)\pm\sqrt{-10^{2}-4(20)(-30)}} {2(20)}$

$x=\frac{10\pm\sqrt{2,500}} {40}$

$x=\frac{10\pm50} {40}$

$x=\frac{10+50} {40}=1.5$

$x=\frac{10-50} {40}=-1$

The roots are x=-1 and x=1.5

The sum of the roots are

$-1+1.5=0.5$ ----> is ok

5 0

3 years ago