calculate the nominal interest per annum if the effective rate was 11.4% p.a compounded half yearly for 5 years

Answer 1

ten periods at .057 per period

1.057^10 = 1.74

for five one year compoundings:
x^5 = 1.74
5 log x = log 1.74 = .24055
log x = .04810984
10^log x = x = 1.117
or 11.7 %