Answer: 6.93 years
Step-by-step explanation:
Given
Rate of interest is 
Future value is given by 
For the investment to double itself, i.e. 
It takes around 6.93 years to double the investment.
If this is just an expression, then all you have to do is combine like terms, or groups of numbers and variables that have the same variable.
When simplified, you get the equation
-12+ 16r or
-18+6+3r+13r=16r-12
The fraction in the picture is 1/8 .
That's equivalent to 12.5 %.
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Maybe what you want is the whole mixed number changed to percent.
-- The 5 alone is 500% .
-- The 1/8 alone is 12.5% .
-- When you puttum together and addum up,
(5 + 1/8) = (500% + 12.5%) = 512.5% .
20 because 70 divide by = 35
