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2 years ago

An item costs S430 before tax, and the sales tax is $17.20.

Mathematics

1 answer:

Ronch [10]2 years ago

5 0

Answer:

Step-by-step explanation:

430

x4%

_________

$17.20+ $430= $447.20

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H(x)=-2x^(2)+3x what is the value of h(-3)

jarptica [38.1K]

Answer:

h(-3) = -27

Step-by-step explanation:

Given that,

$h(x)=-2x^{(2)}+3x$

We need to find the value of h(-3).

Put x = -3 in the given expression.

$h(-3)=-2(-3)^{(2)}+3(-3)\\\\=-2\times 9-9\\\\=-27$

So, the value of h(-3) is equal to -27.

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2 years ago

The ideal (daytime) noise-level for hospitals is 45 decibels with a standard deviation of 10 db; which is to say, this may not b

WINSTONCH [101]

Answer:

(a) A 99% confidence interval for the actual mean noise level in hospitals is (44.02 db, 49.98 db).

(b) We can be 90% confident that the actual mean noise level in hospitals is 47 db with a margin of error of 1.89 db.

(c) Unless our sample (of 81 hospitals) is among the most unusual 2% of samples, the actual mean noise level in hospitals is between 44.41 db and 49.59 db.

Step-by-step explanation:

The problem is incomplete. The questions are:

(a) A 99% confidence interval for the actual mean noise level in hospitals is (44.02 db, 49.98 db).

For a 99% CI, the value of z is z=2.58

Then, the confidence interval for the mean is:

$M-z\sigma/\sqrt{n}\leq\mu\leq M-z\sigma/\sqrt{n}\\\\47-2.58*10/\sqrt{75} \leq\mu\leq47+2.58*10/\sqrt{75}\\\\47-2.98\leq\mu\leq47+2.98\\\\44.02\leq\mu\leq 49.98$

(b) We can be 90% confident that the actual mean noise level in hospitals is 47 db with a margin of error of 1.89 db.

For a 90% CI, the value of z is z=1.64.

Then, we can calculate the margin of error as:

$E=z*\sigma/\sqrt{n}=1.64*10/\sqrt{75}=1.89$

(c) Unless our sample (of 81 hospitals) is among the most unusual 2% of samples, the actual mean noise level in hospitals is between 44.41 db and 49.59 db.

The 2% tails data corresponds, in the standard normal distirbution, to the values of z whose absolute value is higher than 2.33.

The values of db for these critical values are:

$X_1=M+z_1*\sigma/\sqrt{n}=47+(-2.33)*10/\sqrt{81}=47-2.59=44.41\\\\\\ X_2=M+z_2*\sigma/\sqrt{n}=47+(2.33)*10/\sqrt{81}=47+2.59=49.59$

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3 years ago

Did the greeks use erasers in geometric construction?

Anika [276]

Yes,the famous geometric construction a pair of compasses, an unmarked ruler, and (of course!) a pencil and an eraser.

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3 years ago

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Which of the following expressions is the conjugate of a complex number with 2 as the real part and 3i as the imaginary part?

lbvjy [14]

The complex number is represented as 2 + 3i. The conjugate of the complex number is the number with equal real part and imaginary part equal in magnitude but opposite in sign. Therefore, the correct answer is option B. The conjugate of the complex number is 2 − 3i.

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2 years ago

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Decide whether you would use a permutation, a combination, or neither. Next, write the solution using permutation notation or co

Zepler [3.9K]

Answer:

Permutation is used.

No. of arrangements = 1260

Step-by-step explanation:

Permutation is used for choosing & arrangement of 'r' out of 'n' objects, when sequence is important.

Total no. of alphabets in CORRECT = 7

C is repeated twice, R is repeated twice

So, Total No. of arrangements = 7 !

(2!)(2!)

= 5040 / 4

= 1260

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3 years ago