334

$q=\frac{5{,}76\%}{4}=1{,}44\%$

$n=3\cdot4=12$

$A=10800\cdot1{,}0144^{12}\cdot\frac{1-1{,}0144}{1-1{,}0144^{12}}=986{,}4469...\approx986{,}45€$
$A\cdot n\approx11837{,}37€$
$11837{,}37-10800€=1037{,}37€$