Answer:
C(60) = 2.7*10⁻⁴
t = 1870.72 s
Step-by-step explanation:
Let x(t) be the amount of chlorine in the pool at time t. Then the concentration of chlorine is
C(t) = 3*10⁻⁴*x(t).
The input rate is 6*(0.001/100) = 6*10⁻⁵.
The output rate is 6*C(t) = 6*(3*10⁻⁴*x(t)) = 18*10⁻⁴*x(t)
The initial condition is x(0) = C(0)*10⁴/3 = (0.03/100)*10⁴/3 = 1.
The problem is to find C(60) in percents and to find t such that 3*10⁻⁴*x(t) = 0.002/100.
Remember, 1 h = 60 minutes. The initial value problem is
dx/dt= 6*10⁻⁵ - 18*10⁻⁴x = - 6* 10⁻⁴*(3x - 10⁻¹) x(0) = 1.
The equation is separable. It can be rewritten as dx/(3x - 10⁻¹) = -6*10⁻⁴dt.
The integration of both sides gives us
Ln |3x - 0.1| / 3 = -6*10⁻⁴*t + C or |3x - 0.1| = e∧(3C)*e∧(-18*10⁻⁴t).
Therefore, 3x - 0.1 = C₁*e∧(-18*10⁻⁴t).
Plug in the initial condition t = 0, x = 1 to obtain C₁ = 2.9.
Thus the solution to the IVP is
x(t) = (1/3)(2.9*e∧(-18*10⁻⁴t)+0.1)
then
C(t) = 3*10⁻⁴*(1/3)(2.9*e∧(-18*10⁻⁴t)+0.1) = 10⁻⁴*(2.9*e∧(-18*10⁻⁴t)+0.1)
If t = 60
We have
C(60) = 10⁻⁴*(2.9*e∧(-18*10⁻⁴*60)+0.1) = 2.7*10⁻⁴
Now, we obtain t such that 3*10⁻⁴*x(t) = 2*10⁻⁵
3*10⁻⁴*(1/3)(2.9*e∧(-18*10⁻⁴t)+0.1) = 2*10⁻⁵
t = 1870.72 s
Answer:
d
Step-by-step explanation:
Answer:
75 ft
Step-by-step explanation:
Here we are given a right angled triangle with a known angle of 20°, length of the hypotenuse to be 80 and we are to find the length of the base x.
For that, we can use the formula for cosine for which we need an angle and the lengths of base and hypotenuse.
So putting in the given values to get:
Therefore, the value of x is the closest to 75 ft.
$500 principal earning 4% compounded quarterly, after 6 years.
A.
$632.66
B.
$530.76
C.
$634.87
Answer:
C.
$634.87
Step-by-step explanation:
A=500×(1+0.04÷4)^(4×6)
A=634.87
Answer: 50 cups of coffee
Step-by-step explanation:
Let x represent the number of cups of coffee that it will take for the cost at Dunkin Donuts to be the same as having a Keurig and k-cups.
He orders a coffee from Dunkin Donuts and it costs him $3.50 everyday. It means that the cost of ordering x cups would be 3.5x.
The Keurig is $150 and each k-cup costs $0.50. It means that the cost of ordering x cups would be 150 + 0.5x.
For the ordering cost to be the same, it means that
3.5x = 150 + 0.5x
3.5x - 0.5x = 150
3x = 150
x = 150/3
x = 50
Answer:
fourth degree monomial
Step-by-step explanation:
This is the answer by definition.
Answer:
Step-by-step explanation: