Gracias a @D Stanley por la sugerencia
+------------------+-----------+--------------+--------------+---------+---------------------+
| |deposits |principals** |interest rate |interest*|accumulated interest |
+------------------+-----------+--------------+--------------+---------+---------------------+
|2nd half 2010 |100 |100 |0.07 |3.53 |3.53 |
|1st half 2011 |200 |203.53 |0.07 |7.19 |10.72 |
|2nd half 2011 |300 |310.72 |0.07 |10.97 |21.69 |
|1st half 2012 |400 |421.69 |0.07 |14.89 |36.57 |
|2nd half 2012 |500 |536.57 |0.07 |18.94 |55.52 |
|1st half 2013 |600 |655.52 |0.07 |23.14 |78.66 |
|2nd half 2013 |800 |878.66 |0.05 |22.10 |100.77 |
|1st half 2014 |1000 |1100.77 |0.05 |27.69 |128.46 |
|2nd half 2014 |3200 |3328.46 |0.06 |100.60 |229.06 |
|1st half 2015 |3400 |3629.06 |0.06 |109.69 |338.75 |
|2nd half 2015 |3600 |3938.75 |0.06 |119.05 |457.80 |
|1st half 2016 |3800 |4257.80 |0.06 |128.69 |586.49 |
|2nd half 2016 |4000 |4586.49 |0.06 |138.63 |725.12 |
|1st half 2017 |4200 |4925.12 |0.06 |148.86 |873.98 |
|2nd half 2017 |4400 |5273.98 |0.06 |159.41 |1033.38 |
|1st half 2018 |4600 |5633.38 |0.06 |170.27 |1203.65 |
|2nd half 2018 |4800 |6003.65 |0.06 |181.46 |1385.11 |
+------------------+-----------+--------------+--------------+---------+---------------------+
*La fórmula utilizada para calcular el interés de la columna es
interest = (principal * (1 + (interest rate / 4) ) ^ (0.5 * 4) ) - principal
0.5 is a half of a year
4 is the number of compounding periods
** los directores son los depósitos de + interés acumulado hasta el comienzo del período
Según mis cálculos se supone que él ha 6185.11 en su cuenta al final de 2018
- 6185.11 = 4800 + 1385.11
- 6185.11 = 6003.65 + 181.46