Duration of swap

For fixed rate bond, are we to assume 75% of the full time period in all cases as duration or is that only for semi-annual payment bonds etc?

Yes. for monthly too, it assumes that a fixed-rate bond has a duration that is 75% of its maturity (this is a dickish question, they will almost certainly just give you the swap duration on the exam)


swap duration = 0.5 / (#pmts) - k*(maturity)

where k = % maturity

most cases assuming k=75% but if they explicitly tell you otherwise, use the new info