Answer: She started with $160.
It will take 6 weeks before she has less than half of what she originally invested.
Step-by-step explanation:
If her money is decreasing in value by 11% each week, it means that the rate at which it is decreasing is exponential.
We would apply the formula for exponential decay which is expressed as
A = P(1 - r)^t
Where
A represents the value of the investment after t weeks.
t represents the number of weeks.
P represents the initial value of the investment.
r represents rate of depreciation.
From the information given,
A = $142.40
r = 11% = 11/100 = 0.11
t = 1
Therefore
142.40 = P(1 - 0.11)^1
142.40 = P(0.89)
P = 142.4/0.89
P = 160
For her to have half of what she invested originally, then
80 = 160(0.89)^t
80/160 = (0.89)^t
0.5 = (0.89)^t
Taking log of both sides to base 10
Log 0.5 = log0.89^t = tlog0.89
- 0.3010 = - 0.051t
t = - 0.3010/- 0.051
t = 5.9
Approximately 6 weeks
Answer:
1001.
Step-by-step explanation:
1. if B=11*13; h=7, then
2. V=11*13*7=1001.
Answer: The book costs $10 and the pen costs $4✔️
Step-by-step explanation:
Let B the cost of the book and let P the cost of the pen.
Then we know:
The book and the pen cost $14:
B + P = $14 } Equation 1
We also know:
The cost of the book is two dollars more than twice the cost of the pen.
B = 2P + $2 } Equation 2
Now we can substitute the value of B from the equation 2 in the equation 1:
2P + $2 + P = $14
3P = $14 - $2 = $12
P = $12/3 = $4 , cost of the pen
Since we know the value of B from the equation 2, we can calculate B:
B = 2P + $2 = 2x$4 + $2 = $8 + $2 = $10 , cost of the book
Answer: The book costs $10 and the pen costs $4✔️
<h3>Verify </h3>
We can substitute these values in equations 1 and 2 and check the results:
B + P = $14 } Equation 1
$10 + $4 = $14 ✔️check!
B = 2P + $2 } Equation 2
$10 = 2x$4 + $2 = $8 + $2 = $10 ✔️check!
<h2><em>Spymore</em></h2>
Va = 3.14 x 12^2 x 6/3 = 904.32
Vb = 3.14 x 6^2 x 24/3 = 904.32
so VA = VB