Hi,
a) A=20000(1+.05/2)^(2*3) |P = $20,000,r= .05, t = 3yr and n = 2
b) A=20000(1+.05/4)^(4*3) |P = $20,000,r= .05 , t = 3yr and n = 4
c) A=20000(1+.05/12)^(12*3) |P = $20,000,r= .05 , t = 3yr and n = 12
2) A=20000e^(.05*3 ) |P = $20,000,r= .05 , t = 3yr, compounded continuously