ABC Corp. is considering an investment project over the next period. It has an equal chance of success and failure. If it succeeds, the firm's assets will have a market value of $40 million, and if it fails, the market value will drop to $10 million. The current market value of the firm's asset is $25 million. Also, the firm currently has bonds outstanding with $15 million of promised payment to bondholders at their maturity, which is the end of the period. What is the firm's equity value? Assume that the risk-free rate over the next period is 10%. (Hint: Use the binomial approach)