Exercise $4.$ Consider the binomial asset pricing world where at time $t=0,$ a

share of stock $costs{S}_0=50.$ At time $t=1,$ we flip a coin, and the stock is worth

$S_1(H)=100$ or $S_1(T)=50$ if heads or tails occurs respectively. Assume the

probability of heads is $p=\frac{1}{2}.$ If the risk$-$free interest rate is $r=0\mathrm{.}1,$ what is

the equity premium?