I believe it is A and D. All you have to do is add them all together and if both sides are the same then its a correct answer.
CDAB
4.2 (convert to frac on ur own)
12.5=x
CB= 14.5
AB= 8.82
To solve this problem you must apply the proccedure shown below:
1. You must apply the following formula:
Where 
is the future value, 
is the present value, 
is the interest rate and 
is the time in years.
2. You have that the bank will double your money in 
years. Therefore:
3. Substitute values into the formula and solve for , as following:
4. By applying natural logarithm, you have:
%
The answer is: 
%
<span>Simplifying
k3 + 4k2 + 4k = -1k3 + 10k
Reorder the terms:
4k + 4k2 + k3 = -1k3 + 10k
Reorder the terms:
4k + 4k2 + k3 = 10k + -1k3
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