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Natasha2012 [34]

3 years ago

13

A chemist is using 328 milliliters of a solution of acid and water. If 14.4% of the solution is acid, how many milliliters of ac

id are there?.

1 answer:

gregori [183]3 years ago

5 0

Answer:

47.432 (rounds to 47.4 or 47.43)

Step-by-step explanation:

14.4 * 328/100 = 47.232

You might be interested in

If C4=15 and C7=14, what is the result of the logical expression C4>C7 true or false

kvasek [131]

The answer is True because just plug in the numbers

C4=15 and C7=14

logical expression

C4>C7

15>14

That reads to 15 is greater than 14, which is true

3 0

2 years ago

The prior probabilities for events A1 and A2 are P(A1) = 0.20 and P(A2) = 0.80. It is also known that P(A1 ∩ A2) = 0. Suppose P(

Umnica [9.8K]

Answer:

(a) $A_1$ and $A_2$ are indeed mutually-exclusive.

(b) $\displaystyle P(A_1\; \cap \; B) = \frac{1}{20}$ , whereas $\displaystyle P(A_2\; \cap \; B) = \frac{1}{25}$ .

(c) $\displaystyle P(B) = \frac{9}{100}$ .

(d) $\displaystyle P(A_1 \; |\; B) \approx \frac{5}{9}$ , whereas $P(A_1 \; |\; B) = \displaystyle \frac{4}{9}$

Step-by-step explanation:

<h3>(a)</h3>

$P(A_1 \; \cap \; A_2) = 0$ means that it is impossible for events $A_1$ and $A_2$ to happen at the same time. Therefore, event $A_1$ and $A_2$ are mutually-exclusive.

<h3>(b)</h3>

By the definition of conditional probability:

$\displaystyle P(B \; | \; A_1) = \frac{P(B \; \cap \; A_1)}{P(B)} = \frac{P(A_1 \; \cap \; B)}{P(B)}$ .

Rearrange to obtain:

$\displaystyle P(A_1 \; \cap \; B) = P(B \; |\; A_1) \cdot P(A_1) = 0.25 \times 0.20 = \frac{1}{20}$ .

Similarly:

$\displaystyle P(A_2 \; \cap \; B) = P(B \; |\; A_2) \cdot P(A_2) = 0.80 \times 0.05 = \frac{1}{25}$ .

<h3>(c)</h3>

Note that:

$\begin{aligned}P(A_1 \; \cup \; A_2) &= P(A_1) + P(A_2) - P(A_1 \; \cap \; A_2) = 0.20 + 0.80 = 1\end{aligned}$ .

In other words, $A_1$ and $A_2$ are collectively-exhaustive. Since $A_1$ and $A_2$ are collectively-exhaustive and mutually-exclusive at the same time:

$\displaystyle P(B) = P(B \; \cap \; A_1) + P(B \; \cap \; A_2) = \frac{1}{20} + \frac{1}{25} = \frac{9}{100}$ .

<h3>(d)</h3>

By Bayes' Theorem:

$\begin{aligned} P(A_1 \; |\; B) &= \frac{P(B \; | \; A_1) \cdot P(A_1)}{P(B)} \\ &= \frac{0.25 \times 0.20}{9/100} = \frac{0.05 \times 100}{9} = \frac{5}{9}\end{aligned}$ .

Similarly:

$\begin{aligned} P(A_2 \; |\; B) &= \frac{P(B \; | \; A_2) \cdot P(A_2)}{P(B)} \\ &= \frac{0.05 \times 0.80}{9/100} = \frac{0.04 \times 100}{9} = \frac{4}{9}\end{aligned}$ .

6 0

2 years ago

SOLVE x^4 − 15x^2 − 16 = 0 <br> What are the roots of the equation?

kakasveta [241]

Answer:

roots : 4, -4, i, -i

Step-by-step explanation:

This gets a bit tricky.

We have to substitude x^2 as u in this problem.

Now to rewrite x^4 − 15x^2 − 16 = 0 with u, we get

u^2 - 15u - 16 = 0

( u - 16) (u + 1)

U = 16

U = -1

<em>This is not the end of the problem. </em>

Now we have to substitute x^2 back to u.

x^2 = 16 --> we get the roots 4 and -4

x^2 = -1 --> we get the roots i and -i

tadah!

8 0

2 years ago

In circle T, PTQ = RTS.<br> What is the measure of PQ?<br> 24°<br> 33°<br> 48°<br> 66°

weqwewe [10]

Answer:

The correct option is D

66°

Step-by-step explanation:

Given that ∠PTQ ≅ ∠RTS

The measure of the arc SR = 66°

So ∠RTS = 66°

But also, ∠PTQ ≅ ∠RTS

Therefore ∠PTQ = 66°

and the measure of the arc PQ = ∠PTQ

Therefore, measure of the arc PQ is 66°.

4 0

3 years ago

Building A is 400 feet tall and Building B is 300 feet tall. Johnny is standing in between the two building. The angle of elevat

Free_Kalibri [48]

Answer:

389 feets apart

Step-by-step explanation:

Given that:

Building A

Height = 400feets

Angle of elevation = 70°

Building B:

Height = 300 feets

Angle of elevation = 52°

Distance from the foot of building A to where Jonny is standing = x (see attached picture)

Using trigonometry :

Tanθ = opposite / Adjacent

Tan 70 = 400/ x

2.7474774x = 400

x = 145.58809 feets

Distance from the foot of building B to where Jonny is standing = y (see attached picture)

Using trigonometry :

Tanθ = opposite / Adjacent

Tan 52 = 300/ y

1.2799416y = 300

y = 145.59

y = 234.38568 feets

x + y = distance between the two buildings

(145.58809 + 234.38568) feets

= 379.97377

= 380 feets apart

5 0

2 years ago