on the bad side
For a score with a range between 300-850, a credit score of 700 or above is generally considered good. A score of 800 or above on the same range is considered to be excellent. Most credit scores fall between 600 and 750. Hope that this helps you and have a great day :)
Answer:
If you have a quantity X of a substance, with a decay constant r, then the equation that tells you the amount of substance that you have, at a time t, is:
C(t) = X*e^(-r*t)
Now, we know that:
We have 2000g of substance A, and it has a decay constant of 0.03 (i assume that is in 1/year because the question asks in years)
And we have 3000 grams of substance B, with a decay constant of 0.05.
Then the equations for both of them will be:
Ca = 2000g*e^(-0.03*t)
Cb = 3000g*e^(-0.05*t)
Where t is in years.
We want to find the value of t such that Ca = Cb.
So we need to solve:
2000g*e^(-0.03*t) = 3000g*e^(-0.05*t)
e^(-0.03*t) = (3/2)e^(-0.05*t)
e^(-0.03*t)/e^(-0.05*t) = 3/2
e^(t*(0.05 - 0.03)) = 3/2
e^(t*0.02) = 3/2
Now we can apply Ln(x) to both sides, and get:
Ln(e^(t*0.02)) = Ln(3/2)
t*0.02 = Ln(3/2)
t = Ln(3/2)/0.02 = 20.3
Then after 20.3 years, both substances will have the same mass.
Answer: the speed of the plane in still air is 135 km/h
the speed of the wind is 23 km/h
Step-by-step explanation:
Let x represent the speed of the plane in still air.
Let y represent the speed of the wind.
Flying to England with a tailwind a plane averaged 158km/h. This means that the total speed of the plane is (x + y) km/h. Therefore,
x + y = 158 - - - - - - - - - - - - - -1
On the return trip, the plane only averaged 112 km/h while flying back in the same wind. This means that the total speed of the plane is (x - y) km/h. Therefore,
x - y = 112 - - - - - - - - - - - - - -2
Adding equation 1 to equation 2, it becomes
2x = 270
x = 270/2 = 135 km/h
Substituting x = 135 into equation 2, it becomes
135 - y = 112
y = 135 - 112
y = 23 km/h
