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
If it is a fraction like (3a-3b)/(3a+12b)
= [3(a-b)]/[3(a+4b)]
= (a-b)/(a+4b)
Answer:
The null and alternative hypotheses are:
Under the null hypothesis, the test statistic is:
Where:
is the sample mean
is the sample standard deviation
is the sample size
Now, we can find the right tailed t critical value at 0.01 significance level for df = n-1 = 10 - 1 = 9 using the t distribution table. The t critical value is given below:
Since the test statistic is less than the t critical value, we therefore, fail to reject the null hypothesis and conclude that there is not sufficient evidence to support the claim that the people do better with the new edition.
9(2x-1)=3(x+2)+3x
18x-9=3x+6+3x
18x-9=6x+6
18x-6x=6+9
12x=15
x=15/12
x=5/4
The Intersecting Secant Theorem says
EC × ED = EB × EA
(x+4)(x+4+1) = (x+1)(x+1+11)
(x+4)(x+5)=(x+1)(x+12)
x^2 + 9x + 20 = x^2 + 13 x + 12
8 = 4x
x = 2
Check:
6(7)=42
3(14)=42, good
Answer: 2
