For simple interest:
$$I = PRT$$
$$I = 21000\times{0.095}\times{3}$$
$$I = 5985.00$$$
(note this is the interest, not the new sum)
For Compound interest:
$$A = P(1+r)^n$$
$$A = 21000\times{(1+0.095)^3}$$
$$A = 21000 \times {1.312932375}$$
$$A = 27571.58$$$
(this is the whole new amount)
For simple interest:
$$I = PRT$$
$$I = 21000\times{0.095}\times{3}$$
$$I = 5985.00$$$
(note this is the interest, not the new sum)
For Compound interest:
$$A = P(1+r)^n$$
$$A = 21000\times{(1+0.095)^3}$$
$$A = 21000 \times {1.312932375}$$
$$A = 27571.58$$$
(this is the whole new amount)