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2 years ago

PLZZZ HELPPPP ILL MARK BRAINLIEST TO FIRST AND CORRECT ANSWER THAT HAS WORK AND A THX TO SECOND AND CORRECT ANSWER.

Mathematics

1 answer:

sergij07 [2.7K]2 years ago

3 0

Answer:

3.9 - C

Step-by-step explanation:

This forms a triangle with a base of 2.5 and a height of 3.

Using the Pythagorean Theorem, 2.5^2 + 3^2 = c^2

This gives you the answer 3.91.

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What is the equivalent of 6x-8y?

liberstina [14]

Plug y=-5 into the equation
6x+8(-5)=-22
6x-40=-22
6x=-22+40
6x=18
x=3

6 0

3 years ago

One positive number is 14 less than another positive number. If the reciprocal of the smaller number is added to five times the

Kipish [7]

Let's call the two numbers $s$ and $l$ .

Given these variables, we can say: $s = l - 14$ , based on the first sentence in the problem.

Also, remember that the reciprocal of a number is simply 1 divided by the number. Thus, we can say that:

$\dfrac{1}{s} + 5\Big( \dfrac{1}{l} \Big) = \dfrac{1}{4}$

To solve, we can simply substitute $l -14$ in for $s$ in the second equation and solve.

$\dfrac{1}{l - 14} + \dfrac{5}{l} = \dfrac{1}{4}$

Set up

$\dfrac{l}{l(l - 14)} + \dfrac{5(l - 14)}{l(l - 14)} = \dfrac{1}{4}$

Get terms on the left side to a common denominator for easier addition

$\dfrac{l + 5l - 70}{l(l - 14)} = \dfrac{1}{4}$

Simplify

$4(6l - 70) = l(l - 14)$

Cross multiplication ( $\frac{a}{b} = \frac{c}{d} \Rightarrow ad = bc$ )

$24l - 280 = l^2 - 14l$

Simplify

$l^2 - 38l + 280 = 0$

Subtract $24l - 280$ from both sides of the equation

$(l - 10)(l - 28) = 0$

Factor left side of the equation

$l = 10, 28$

Zero Product Property

Now, notice that we have found two solutions, but the problem is only asking for one. This likely means that one of our solutions is extraneous. Let's take a look. Remember that the smaller positive number is equal to 14 less than the larger number. However,

$s = 10 - 14 = -4$ ,

Since $s$ is not positive in this case, $l = 10$ is not a solution.

Thus, $l = 28$ is our only solution. In this case,

$s = 28 - 14 = 14$ ,

which means that the smaller number is 14 and the larger number is 28.

5 0

2 years ago

An English professor assigns letter grades on a test according to the following scheme. A: Top 15% of scores B: Scores below the

lisabon 2012 [21]

Answer:

59 to 66

Step-by-step explanation:

Mean test scores = u = 74.2

Standard Deviation = $\sigma$ = 9.6

According to the given data, following is the range of grades:

Grade A: 85% to 100%

Grade B: 55% to 85%

Grade C: 19% to 55%

Grade D: 6% to 19%

Grade F: 0% to 6%

So, the grade D will be given to the students from 6% to 19% scores. We can convert these percentages to numerical limits using the z scores. First we need to to identify the corresponding z scores of these limits.

6% to 19% in decimal form would be 0.06 to 0.19. Corresponding z score for 0.06 is -1.56 and that for 0.19 is -0.88 (From the z table)

The formula for z score is:

$z=\frac{x-u}{\sigma}$

For z = -1.56, we get:

$-1.56=\frac{x-74.2}{9.6}\\\\ x = 59$

For z = -0.88, we get:

$-0.88=\frac{x-74.2}{9.6}\\\\ x = 66$

Therefore, a numerical limits for a D grade would be from 59 to 66 (rounded to nearest whole numbers)

7 0

3 years ago

tatiyna

Answer:

The volume of P is 1728 cubic yards.

Step-by-step explanation:

For similar shapes, the ratio of volumes are defined as:

$\frac{V_{1} }{V_{2}}$ = $(\frac{h_{1} }{h_{2}}) ^{3}$

where h1 and h2 are the heights of each pyramid respectively.

We know that the scale factor of P to Q is 6:1 i.e. the ratio of heights is also 6:1. And the volume of Q is given as 8 cubic yards. so, using the relation defined above we can write:

$\frac{V_{P} }{V_{Q}}$ = $(\frac{h_{P} }{h_{Q}}) ^{3}$