Ineed concerning these credit card and compound monthly problems.

compound interest formula: a = p(1+r/n)^nt

a = amount ( principal + interest)

p = principal ( amount invested)

r = interest rate

n = number of times it is compounded)

t = the time the money was in the bank.

1. p = 12000. r = 4% and n = 12 ( compounded monthly.)

the formula becomes:

a(t) = 1200(1+0.04/12)^12t

2. when compounded continuously, the (1+r/n) in the above formula is replaced with the letter e, which is a mathematical constant and the n is replaced with the rate.

the formula would be :

a(t) = 1200e^0.16t