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1 year ago

8

Joshua is doing a chemistry experiment that calls for a 30% solution of copper sulfate. He has 40ml of 25% solution. How many mi

llimeters of 60% solution should joshua add to obtain the required 30% solution?

1 answer:

Sholpan [36]1 year ago

8 0

Answer:

6 2/3 mL

Step-by-step explanation:

Multiply thru by 100 to get:

1000 + 60x = 30*40 + 30x

30x = 200

x = 6 2/3 mL (amt. of 60% solution needed in the mixture)

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3.18x16 =_____hundredths +_____hundredths=_____hundredths=____

kari74 [83]

3.18x16=50.88 hundredths

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1 year ago

15.6°F in 13 minutes

Scrat [10]

15.6 in 13 minutes? are you asking how it got to 15.6 in 13 minutes?

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1 year ago

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A website reports that 70% of its users are from outside a certain country, and 60% of its users logon the website every day. Su

JulijaS [17]

Answer:

The value is $P (I | L ) = 0.63$

The probability has increased

Step-by-step explanation:

From the question we are told that

The percentage that are from outside the country is $P(O) = 0.70$

The percentage that logs on everyday is $P(L) = 0.60$

The percentage that logs on everyday that are from the inside the country is $P(L | I) = 0.80$

Generally using Bayes' Rule the probability that a person is from the country given that he logs on the website every day is mathematically represented as

$P (I | L ) = \frac{P(I)* P(L|I)}{ P(O) *P(L|O) + P(I) *P(L|I) }$

Where $P(I)$ is the percentage that are from inside that country which is mathematically represented as

$P(I) = 1 - P(O)$

$P(I) = 1 - 0.70$

$P(I) = 0.30$

And $P(L| O)$ is percentage that logs on everyday that are from the outside the country which is evaluated as

$P(L| O) = 1- P(L| I)$

$P(L| O) = 1- 0.80$

$P(L| O) = 0.20$

$P (I | L ) = \frac{ 0.3* 0.80 }{ 0.7 *0.20 + 0.3 * 0.8 }$

$P (I | L ) = 0.63$

Given that the percentage that are from inside that country is $P(I) = 0.30$

and that the probability that a person is from the country given that he logs on the website every day is $P (I | L ) = 0.63$

We see that the additional information increased the probability

5 0

1 year ago

Frank has three times as many dollars as Deandra, and Charlie has 20 more dollars than Frank. If Charlie has $65, how much money

My name is Ann [436]

Answer:

$15

Step-by-step explanation:

Let Frank be f

Deandra be d and

Charlie be c

f = 3d ......(i)

c=$20+f.....(ii)

c=$65........(iii)

Equate (ii) and (iii)

$20+f = $65

f = $45.......(iv)

Equate (i) and (iv)

3d = $45

d = $15

Deandra has $15.

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1 year ago

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In this problem you will estimate the heat lost by a typical house, assuming that the temperature inside is tin=20∘c and the tem

san4es73 [151]

Step 1:

<span>Calculate the effective thermal conductivity of the wall or ceiling:
</span>
K_eff = [ (13 ÷ 8)(0.12) + (16 - (13 ÷ 8)) × (0.04)] ÷ 16

K_eff =<span> [ 0.195 + 0.565] </span>÷<span> 16

</span>
K_eff = 0.76 ÷ 16

K_eff = 0.0475 W/ (m K)

Step 2:

Calculate <span>the interior ceiling area:

</span>Area of each of the interior side walls = <span>8.82 m x 8.64 m
= 76.2 m</span>²

Area of the interior ceiling = 8.64 m × <span>8.64 m
</span> = 74.6 m²

H = - k·A·(Δ - T) ÷ <span>(thickness)
</span>
H = - 0.0475 ÷ (379.45 × 20) ÷ 45/8

H = - ( - 0.95 × 379.45 ) ÷<span> 0.1429
</span>
H = <span>2.52 kW </span>

3 0

2 years ago