Suppose that the U$.$S$.$ dollar$-$pound sterling spot exchange rate equals $$1\mathrm{.}60/,$ while the $360-$day forward rate is $$1\mathrm{.}64/.$ The yield on a one$-$year U$.$S$.$ treasury bill is $9\%$ and that on a one$-$year U$.$K$.$ treasury bill is $8\%.$

a$.$ Calculate the covered interest differential.