The one$-$period bonds in our model pay a single interest payment or $$coupon$$ of $R and

a principal of $$1.$ Alternatively, we could consider a one$-$period discount bond like a

U$.$S$.$ Treasury bill. This type of asset has no coupons but pays a principal of $$1$ next

period. Let PB be the dollar price for each unit of discount bonds, where each unit is a

claim to $$1$ next period

What is the one$-$period rate of interest on discount bonds?