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.
Truck is 30% less than bus
40 divided by 1.3 = 30.77
Car is 75% less than truck
30.77 divided by 1.75. = 17.58 feet
Answer:
This is not the answer this is the trick to find it
Step-by-step explanation:
The points after reflection will follow points equal but different direction, to the path followed before the reflection. So, if the line would cover 3.5 on the x and 5 on the y; it will reflect symmetrically giving you the formula to get your answer.
17
85/17 is 5 and 51/17 is 3
12x - 8y = -12
6x + 4y = -30
Multiply the 2nd equation by 2, to make the Y coefficients opposite:
6x + 4y = -30 x 2 = 12x + 8y = -60
Now add the two equations:
12x -8y = -12 + 12x +8y = -60
= 24x = -72
Divide bothe sides by 24 to solve for x:
x = -72/24
x = -3
Now replace x with -3 in the first equation to solve for y:
12(-3) - 8y = -12
-36 - 8y = -12
Add 36 to each side:
-8y = 24
Divide both sides by -8 to solve for y:
y = 24 / -8
y = -3
X = -3 and y = -3
(-3,-3)
