A fruit retailer buys $50$ pounds of apples from the wholesale market every day. The retailer has observed that$20\%$ of the apples bought each time are not of good quality.

Since it is not possible for the retailer to check each apple before$$ buying, how much should he pay for each pound if he values good apples at$$ $$1\mathrm{.}40$ per pound and has a value of zero for$$ bad$-$quality apples?