Question
Consider an underlying with $S_0 = 25$. We have the following derivatives contract: this contract pays $1$ if $S_T \ge 24$ and $-1$ otherwise. We have access to the following binary calls (a contract paying $1$ if $S_T \ge K$ and $0$ otherwise). The calls are given in the format of $(\text{Strike } K, \text{Price } C_0)$ $$ \begin{align*} (25, 0.6) \\ (24, 0.73) \\ (23, 0.88) \\ \end{align*} $$ Give the time-$0$ price of the derivatives contract. Bonds pay $1$ at time-$T$ and have time-$0$ price $B_0 = 0.9$.