All categories

2 years ago

PLS HURRY THIS IS REALLY HARD!(FOR ME)

Mathematics

1 answer:

babunello [35]2 years ago

8 0

Answer:

She needs about 398 more dollars

Step-by-step explanation: The price of the whiteboard is $989. Add the money from what she collected and the fundraising. 485+106 then you take that and subtract it from 989.

Hope this helped!

You might be interested in

Find the total travel time: Depart 5:30 pm MST Arrive 9:20 pm CST

Len [333]

Answer:

2 hours 50 minutes

Step-by-step explanation:

Mountain Standard Time is 1 hour earlier than Central Standard Time, so the departure time is equivalent to 6:30 pm in CST.

The time between 6:30 pm and 9:20 pm is 2 hours 50 minutes.

8 0

2 years ago

arron takes his dog for a walk afer school, he walks 5 blocks east and then 4 blocks north. if he was able to take a direct rout

nlexa [21]

Hi!

We are given the information found in the picture below.

Note: The directions aren't correct, but the triangle works for this problem.

The "direct path" is the hypotenuse of this triangle.

To find this, we use the Pythagorean Theorem, where $a$ and $b$ are 2 legs of the triangle, and $c$ is the hypotenuse, aka the longest side of any triangle:

$a^2+b^2=c^2$

We know $a$ and $b$ and want $c$

$4^2+5^2=c^2$

$16+25=c^2$

$41=c^2$

Therefore, $c$ is approximately $6.403$

3 0

1 year ago

EFV and EDW are straight lines.<br>Find the value of x and of y.

Makovka662 [10]

Answers:

x = 72

y = 83

============================================================

Explanation:

Angle VFG is 50 degrees. The angle adjacent to this is angle EFG which is 180-50 = 130 degrees.

Angle HDW is 77 degrees. The supplementary angle adjacent to this is 180-77 = 103 degrees which is angle EDH.

Pentagon EFGHD has the following five interior angles

E = x
F = 130
G = 170
H = 65
D = 103

Note that angles F = 130 and D = 103 were angles EFG and EDH we calculated earlier.

For any pentagon, the interior angles always add to 180(n-2) = 180(5-2) = 180*3 = 540 degrees.

This means,

E+F+G+H+D = 540

x+130+170+65+103 = 540

x+468 = 540

x = 72

---------------------------------------

Now focus your attention on triangle THS

We see that the interior angles are

T = y
H = 65
S = 32

The angle H is 65 degrees because it's paired with the other 65 degree angle shown. They are vertical angles.

For any triangle, the angles always add to 180

T+H+S = 180

y+65+32 = 180

y+97 = 180

y = 180-97

y = 83

7 0

2 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

2 years ago

Help me please,Thanks;)

Sindrei [870]

I think its the second choice

8 0

2 years ago

PLS HURRY THIS IS REALLY HARD!(FOR ME)​

PLS HURRY THIS IS REALLY HARD!(FOR ME)