Answer:
The doubling time of this investment would be 9.9 years.
Step-by-step explanation:
The appropriate equation for this compound interest is
A = Pe^(rt), where P is the principal, r is the interest rate as a decimal fraction, and t is the elapsed time in years.
If P doubles, then A = 2P
Thus, 2P = Pe^(0.07t)
Dividing both sides by P results in 2 = e^(0.07t)
Take the natural log of both sides: ln 2 = 0.07t.
Then t = elapsed time = ln 2
--------- = 0.69315/0.07 = 9.9
0.07
The doubling time of this investment would be 9.9 years.
Answer:
160 inches
Step-by-step explanation:
An octagon has 8 sides;
20*8=160
(0,-9) is the y intercept
Answer:
- $8000 at 1%
- $2000 at 10%
Step-by-step explanation:
It often works well to let a variable represent the amount invested at the higher rate. Then an equation can be written relating amounts invested to the total interest earned.
__
<h3>setup</h3>
Let x represent the amount invested at 10%. Then 10000-x is the amount invested at 1%. The total interest earned is ...
0.10x +0.01(10000 -x) = 280
<h3>solution</h3>
Simplifying gives ...
0.09x +100 = 280
0.09x = 180 . . . . . . . subtract 100
x = 2000 . . . . . . divide by 0.09
10000 -x = 8000 . . . . amount invested at 1%
<h3>1.</h3>
$8000 should be invested in the 1% account
<h3>2.</h3>
$2000 should be invested in the 10% account
