If
denotes the sum of the first
terms of a geometric series with first term
and common ratio
, then
Using summation notation, you have
In this case, you have
,
, and
. So the value of the sum is
Rounded to the nearest whole number, the answer would be 3.
Answer:
A
Step-by-step explanation:
There answer
Answer:
420 points
Step-by-step explanation:
multiply 7 by 60
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:
Your answer should be $29.40
Step-by-step explanation:
If you divide 21 by 5 you get 4.2, so each book costs $4.20.
4.2 x 7 = 29.4
Therefore, your total cost for 7 books will be $29.40
I hope this helps!
