Answer: $13,161.264
Step-by-step explanation:
interest rate after first 3 months 9% for 3 months.
I = P x R x T / 100
Where;
I= interest
P= principal
R= interest Rate
= Time
$6000 x 9% x 3 / 100
= $ 1620
Interest for next 3 months 12%
P= $6000 + $1620 = $7620
I= 7620 x 12% x 3 /100 = $2,743.2
Interest after for last 3 months 9%
P= $7620 + $2743.2 = $10,363.2
I = $10,363.2 x 9% x 3 / 100
= $2798.064
Principal after 9months
= $13,161.264