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3 years ago

Which shows the best use of the associative and commutative properties to

Mathematics

1 answer:

OlgaM077 [116]3 years ago

5 0

Answer:

Step-by-step explanation:

So the associative and commutative properties basically say That you can change the orders of the numbers and the answer won't change (for multiplication and addition).

Your answer would be D because they added the numbers with a decimal place together, it makes it easier to look at, and add in your head.

You might be interested in

if P(x)=1+6x-5x^2 represents the profit in selling x thousand Boombotix speakers, how many speakers should be sold to maximize p

Rashid [163]

Answer:

600

Step-by-step explanation:

$p(x) = 1 + 6x - 5x^2$

x max = $-b/2a$

a = -5

b = 6

-6/2(-5) = 6/10 = 3/5 = .6

.6 thousand = 600

600 speakers should be sold.

Alternatively, you can check the vertex of the parabola formed.

8 0

3 years ago

Assume that the empirical rule is a good model for the time it takes for all passengers to board an airplane. The mean time is 4

slamgirl [31]

Answer:

The interval that describes how long it takes for passengers to board the middle 95% of the time is between 40.16 minutes and 55.84 minutes.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 48, \sigma = 4$ .

Which interval describes how long it takes for passengers to board the middle 95% of the time?

This is between the 2.5th percentile and the 97.5th percentile.

So this interval is the value of X when Z has a a pvalue of 0.025 and the value of X when Z has a pvalue of 0.975

Lower Limit

Z has a pvalue of 0.025 when $Z = -1.96$ . So

$Z = \frac{X - \mu}{\sigma}$

$-1.96 = \frac{X - 48}{4}$

$X - 48 = -1.96*4$

$X = 40.16$

Upper Limit

Z has a pvalue of 0.975 when $Z = 1.96$ . So

$Z = \frac{X - \mu}{\sigma}$

$1.96 = \frac{X - 48}{4}$

$X - 48 = 1.96*4$

$X = 55.84$

The interval that describes how long it takes for passengers to board the middle 95% of the time is between 40.16 minutes and 55.84 minutes.

7 0

3 years ago

Granny had 25 bananas.

Ede4ka [16]

Answer:

Step-by-step explanation:

She needs 3 bananas for each loaf of banana bread.

She needs 3*9=27 bananas for 9 loaves.

She has only 25, she is 2 bananas short

7 0

3 years ago

Read 2 more answers

Please could you explain this step by step I’m really stuck.

allochka39001 [22]

Answer:

x = -2.5
x = 2

Step-by-step explanation:

Hello!

We can remove the denominators by multiplying everything by it.

Solve:

$\frac{5}{x + 3} + \frac4{x + 2} = 2$
$5 + \frac{4(x + 3)}{x + 2} = 2(x + 3)$
$5 + \frac{4x + 12}{x + 2} = 2x + 6$
$5(x + 2) +4x + 12 = (2x + 6)(x + 2)$
$5x + 10 + 4x + 12 = 2x^2 + 6x + 4x + 12$
$9x + 22 = 2x^2 + 10x + 12$

Let's make one side equal to 0.

$0 = 2x^2 + x - 10$

Solve by factoring, and then the zero product property.

$0 = 2x^2 + x - 10\\$

Multiply 2 and -10. You get -20. Think of two number that multiply to -20, and add to 1. If we think about the standard form of a quadratic, $ax^2 + bx + c$ , think two numbers that equal "ac" and add up to "b".