1.5r+15=2.25r
Combine like terms: 1.5r+15-1.5r=2.25r-1.5r
15=0.75r
Get the unknown alone: 15/.75=.75/.75r
20=r or r=20 :)
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
The ratio fo boys to girls is 12:16
Answer as an improper fraction = 16/5
Answer as a mixed number = 3 & 1/5
Answer in decimal form = 3.2
All of those values represent the same thing, but written in a different way.
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Explanation:
I'm assuming HM stands for Harmonic Mean in this case.
If so, then we apply the reciprocal operation to each value to get 1/2 and 1/8 (from 2 and 8 respectively).
Add up those fractions:
1/2 + 1/8 = 4/8 + 1/8 = 5/8
Now we'll divide n = 2 over that result. The n = 2 refers to the number of items in the original set.
n divide over (5/8) = 2*(8/5) = 16/5 which is the answer as an improper fraction
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To convert to a mixed number, we can do the following:
16/5 = (15+1)/5
16/5 = 15/5 + 1/5
16/5 = 3 + 1/5
16/5 = 3 & 1/5
Or if you need the answer in decimal form, then using a calculator would get you 16/5 = 3.2
2 halves make up one whole
Hope this helps!
Vote my brainliest!
