What's the question? I'll help with it as much as I can :)
Answer:
point a is positive but point b is negative
It will be understood that population 6,000 billion (6*10^12) in 2017.
If this is not the case, follow the logic and the final number can be adjusted easily.
Mathematical answer:
In 2017: 6,000 billion=6000*10^9 =6*10^12
rate of increase = 1.3% per year (assumed constant)
final year = 2100
Population estimate in 2100
=6*10^12*(1.013^(2100-2017))
=6*10^12*(1.013^(83)
=6*10^12*(2.921352509198383)
=17.528*10^12
=17,528 billion.
Answer: A. divided the difference of the two quantities by the sum of the two quantities.
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Explanation:
The difference of the quantities is 20-15 = 5
The sum of the quantities is 20+15 = 35
Dividing those results leads to 5/35 = 0.142857 which rounds to 0.1429
That converts to 14.29%
This is likely the path Adam took. This path is incorrect. The correct steps are shown below
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Difference = 20-15 = 5
Divide the difference over the original quantity
5/20 = 1/4 = 0.25 = 25%
We have a 25% decrease because the new quantity (15) is smaller than the old quantity (20)
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Here's another way to approach the problem
A = old value = 20
B = new value = 15
C = percent change
C = [ (B-A)/A ] * 100%
C = [ (15-20)/20 ] * 100%
C = (-5/20)*100%
C = -0.25*100%
C = -25%
The negative C value means we have a negative percent change, ie we have a percent decrease. So this is another way to get a 25% decrease.
The opposite of 41 is -41
