Answer:
18.7 years
Step-by-step explanation:
This is a compound interest problem and the following variables have been given;
Principal = 4000; this is the amount o be invested
APR = 9%; this is the compound interest to be earned
Accumulated amount = 20,000
We are required to determine the duration in years. We apply the compound interest formula;


The next step is to introduce natural logarithms in order to determine n;

The number of years required is thus 18.7 years
If you use your subtraction right when you use deceleration as for example like 4.5 from 79 well you know it had to slow down so the correct Answer for this would end up as 17 .5 Try the easy way like
79 dived by 4.5 would get you the same answer but don't divide backwards you will get an in correct answer
hope i helped;)
Answer:
119 R5
divide divide divide divide
My friend... My method wasn't wrong and I couldn't find any mistake on my procedure... Check it out and analyze it by yourself...