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dalvyx [7]
3 years ago
5

A poll of 827 students at Alpha State College found that 61% of those polled preferred a quarter system to a trimester system. E

stimate a 95% confidence interval for the percentage of students who prefer a quarter system.
Mathematics
1 answer:
Nataly [62]3 years ago
6 0
You can do it make your brain on
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What is the answer to this math question?
Anon25 [30]

Answer:

2/7, 4/7, 1/2, 5/6, 3/8

Step-by-step explanation:

i dont know if its correct

7 0
3 years ago
A 500-gallon tank initially contains 220 gallons of pure distilled water. Brine containing 5 pounds of salt per gallon flows int
Wittaler [7]

Answer: The amount of salt in the tank after 8 minutes is 36.52 pounds.

Step-by-step explanation:

Salt in the tank is modelled by the Principle of Mass Conservation, which states:

(Salt mass rate per unit time to the tank) - (Salt mass per unit time from the tank) = (Salt accumulation rate of the tank)

Flow is measured as the product of salt concentration and flow. A well stirred mixture means that salt concentrations within tank and in the output mass flow are the same. Inflow salt concentration remains constant. Hence:

c_{0} \cdot f_{in} - c(t) \cdot f_{out} = \frac{d(V_{tank}(t) \cdot c(t))}{dt}

By expanding the previous equation:

c_{0} \cdot f_{in} - c(t) \cdot f_{out} = V_{tank}(t) \cdot \frac{dc(t)}{dt} + \frac{dV_{tank}(t)}{dt} \cdot c(t)

The tank capacity and capacity rate of change given in gallons and gallons per minute are, respectivelly:

V_{tank} = 220\\\frac{dV_{tank}(t)}{dt} = 0

Since there is no accumulation within the tank, expression is simplified to this:

c_{0} \cdot f_{in} - c(t) \cdot f_{out} = V_{tank}(t) \cdot \frac{dc(t)}{dt}

By rearranging the expression, it is noticed the presence of a First-Order Non-Homogeneous Linear Ordinary Differential Equation:

V_{tank} \cdot \frac{dc(t)}{dt} + f_{out} \cdot c(t) = c_0 \cdot f_{in}, where c(0) = 0 \frac{pounds}{gallon}.

\frac{dc(t)}{dt} + \frac{f_{out}}{V_{tank}} \cdot c(t) = \frac{c_0}{V_{tank}} \cdot f_{in}

The solution of this equation is:

c(t) = \frac{c_{0}}{f_{out}} \cdot ({1-e^{-\frac{f_{out}}{V_{tank}}\cdot t }})

The salt concentration after 8 minutes is:

c(8) = 0.166 \frac{pounds}{gallon}

The instantaneous amount of salt in the tank is:

m_{salt} = (0.166 \frac{pounds}{gallon}) \cdot (220 gallons)\\m_{salt} = 36.52 pounds

3 0
3 years ago
State 7m to 250cm as a ratio in its lowest terms
madam [21]
First you have to convert the numbers to the same units.  Either m to cm or cm to m.
To go from meters to centimeters you multiply the number by 100.
7*100=700cm
Now you have 700cm/250cm.  This needs simplified
I divided each number by 50 to get 14 and 5
14cm/5cm or 14cm:5cm
3 0
3 years ago
Please anyone can give me it's urgent....​
Pavlova-9 [17]

Step-by-step explanation:

From the figure it is clear that:

x+110°=180

x=180-110

x=70

For y:

the left exterior angle of line q is also70.

By the definition of alternate exterior angle:

y=70

<u>Note</u><u>:</u><u>i</u><u>f</u><u> </u><u>you</u><u> </u><u>n</u><u>e</u><u>e</u><u>d</u><u> </u><u>t</u><u>o</u><u> </u><u>a</u><u>s</u><u>k</u><u> </u><u>a</u><u>n</u><u>y</u><u> </u><u>question</u><u> </u><u>please</u><u> </u><u>let</u><u> </u><u>me</u><u> </u><u>know</u><u>.</u>

3 0
3 years ago
Need help solving this. Thanks
Vlad1618 [11]

Answer:

Where is the question?

Step-by-step explanation:

5 0
2 years ago
Read 2 more answers
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