SOLUTION: i cant get my answer in E notation can someone help me please... China is one of the biggest potential markets for US autos. In 2010, there were 1.38E8 car owners in China and the

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: i cant get my answer in E notation can someone help me please... China is one of the biggest potential markets for US autos. In 2010, there were 1.38E8 car owners in China and the      Log On


   

Question 767990: i cant get my answer in E notation can someone help me please...
China is one of the biggest potential markets for US autos. In 2010, there were 1.38E8 car owners in China and the number was growing with a doubling time of 6.3 years. How many car owners would you predict for that country in 2020?Owners (E notation, 2 decimals)???
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
The E notation appears to be similar to scientific notation, the E disignating an exponent on 10.
1.38E8 seems to be a way to show 1.38x10^8.

N=Ie%5E%28kx%29
N=count of car owners after time x
I=initial count of car owners when x is taken at 0
k=a constant
x=time passage in years since 2010


We find k first, using the doubling time.
Let N=2I and x=6.3.
2I=Ie%5E%28k%2A6.3%29
2=e%5E%28k%2A6.3%29
ln%282%29=6.3%2Ak%2Aln%28e%29=6.3%2Ak%2A1=6.3%2Ak
k=%281%2F6.3%29ln%282%29
As a value we can just calculate k=0.110

EQUATION TO APPLY IS highlight%28N=1.38%2A10%5E8%2Ae%5E%280.110%2Ax%29%29

At x=0, year is 2010. I=1.38*10^8
Just be aware this question has an accuracy problem, because the doubling information is based on nearest tenth of a year but year point values are only to the nearest year. Answers can be at best, only estimations.

So with this question, in year 2020, x=2020-2010=10 years.
N=1.38%2A10%5E8%2Ae%5E%280.110%2A10%29
N=1.38%2A10%5E8%2A3.00487
N=4.15%2A10%5E8, might be better to say highlight%284.1%2A10%5E8%29