Gladstone Corporation is about to launch a new product. Depending on the success of the new product, Gladstone may have one of four values next year: $$171,$ $$135,$ $$95,$ and $$80.$ These outcomes are all equally likely, and this risk is diversifiable. Suppose the risk$-$free interest rate is $5\%$ and that, in the event of default, $25\%$ of the value of Gladstone$$s assets will be lost to bankruptcy costs. $($Ignore all other market imperfections, such as taxes.$)$ Initially, Gladstone was an all$-$equity firm with $10$ shares outstanding. Gladstone is going to issue zero$-$coupon debt with a $$105$ face value due next year. How much is the change in stock price? Why answer is $-0\mathrm{.}5413??$