Check whether the given number is a<br> solution of the inequality.<br> 4x + 2 = 14 x = 3

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

How do you determine where to place the decimal point in the product?

frez [133]

Let's look at an example:

2.24 x 21.6

$2.24\\ 21.6\\ ______$

Do normal multiplication and get

48384 This is not correct, until we put the decimals in. To know how to do this, count the number of decimal spaces from the factors. In 2.24, there are 2, because .24. In 21.6 there are 1 because of .6. This mean three places, so 48384 becomes

48.384

~theLocoCoco

7 0

3 years ago

You plan to go snowboarding this weekend in Pennsylvania. The resort charges $15.75 per hour in addition to a $25 deposit to ren

erica [24]

Answer:

$88 in total

Step-by-step explanation:

x = number of hours

y = total cost to rent the snowboard.

$25 is already guaranteed

25 + 15.75x = y

since it is 4 hours from 8:30 a.m. to 12:30 a.m. you put 4 into x.

25+15.75(4) = y

88 = y

6 0

2 years ago

A shoe store recorded the price (in dollars) of 175 pairs of women's shoes and 175 pairs of men's shoes. The data collected was

arsen [322]

Answer:

Most of the men's shoes in the data set cost more than women's shoes.

Step-by-step explanation:

From what I could tell it can't be The price of men's shoes has a higher interquartile range than that of women's shoes. becuse that's false what looks to fit is Most of the men's shoes in the data set cost more than women's shoes. since on the graph more of the mens vaules are bigger

5 0

3 years ago

Liner equations please help with answer!

svetlana [45]

Answer:

n = - $\frac{4}{7}$