Can ypu show me how to solve this question step by step and i have already posted the solution but i dont know how to calculate $17$ EXAMPLE Parity conditions

Parity conditions:

Assume the current EUR$/$USD spot rate is $1\mathrm{.}0537$ and the $6-$month forward exchange

rate is EUR$/$USD $1\mathrm{.}0848.$ The $6-$month nominal interest rate in the Eurozone is $2\mathrm{.}50\%$ p$.$a$.$

Expected inflation in the U$.$S$.$ over the next $6$ months is $7\%$ p$.$a$.$ According to exact parity

conditions, what is the $6-$month real interest rate $($p$.$a$.)$ in the U$.$S$.?$

The $6-$month real interest rate $($p$.$a$.)$ in the U$.$S$.$ is

$(1\mathrm{.}42=1\mathrm{.}43)\%$ per annum.