The formula for depreciation is:
![y=x(1-r)^t](https://tex.z-dn.net/?f=%20y%3Dx%281-r%29%5Et%20)
Where x = Initial value,
y= Amount after depreciation.
r= Rate of depreciation,
t = time (in years)
According to given problem,
x = 1040, y= 944 and t = 12 months =1 year.
So, first step is to plug in these values in the above formula, So,
![944 = 1040(1-r)^1](https://tex.z-dn.net/?f=%20944%20%3D%201040%281-r%29%5E1%20)
944 = 1040 (1 -r)
Divide each sides by 1040.
0.907692308 =1 - r
0.907692308 - 1 = -r Subtract 1 from each sides.
-0.092307692 = -r
So, r = 0.09 or 9%.
Now plug in 0.09 in the above equation to get the depreciation equation. So,
![y = x (1- 0.09)^t](https://tex.z-dn.net/?f=%20y%20%3D%20x%20%281-%200.09%29%5Et%20)
So, ![y = 0.91x^t](https://tex.z-dn.net/?f=%20y%20%3D%200.91x%5Et%20)
b) To find the value of the bike after 5 months,
plug in t = 5 months= 5/12 = 0.41667 years in the above equation of depreciation.
So, ![y= 1040 *(0.91)^{0.41667}](https://tex.z-dn.net/?f=%20y%3D%201040%20%2A%280.91%29%5E%7B0.41667%7D%20%20)
y = 1040 * 0.961465659
y = 999.9242852
y = 1000 (Rounded to nearest integer).
Hence, the value of the bike after 5 months is $1000.
<span>"Simplifying
0.2y = 0.5x + 0.1
Reorder the terms:
0.2y = 0.1 + 0.5x
Solving
0.2y = 0.1 + 0.5x
Solving for variable 'y'.
Move all terms containing y to the left, all other terms to the right.
Divide each side by '0.2'.
y = 0.5 + 2.5x
Simplifying
y = 0.5 + 2.5x"</span>
Answer:
Jeff mows 9 yards of lawn in 30 minutes
Step-by-step explanation:
The equation that models the amount of time (t) in minutes it takes Jeff to mow an average sized yard is
, where n is the number of yards he mows.
To find the number of yards Jeff mows in 30 minutes, we set the equation to 30 and solve for n.
![\implies 2n+12=30](https://tex.z-dn.net/?f=%5Cimplies%202n%2B12%3D30)
Add -12 to both sides:
![\implies 2n=30-12](https://tex.z-dn.net/?f=%5Cimplies%202n%3D30-12)
![\implies 2n=18](https://tex.z-dn.net/?f=%5Cimplies%202n%3D18)
Divide both sides by 2
![\implies \frac{2n}{2}=\frac{18}{2}](https://tex.z-dn.net/?f=%5Cimplies%20%5Cfrac%7B2n%7D%7B2%7D%3D%5Cfrac%7B18%7D%7B2%7D)
![\implies n=9](https://tex.z-dn.net/?f=%5Cimplies%20n%3D9)
Hence Jeff mows 9 yards of lawn in 30 minutes.