### Binomial Model: Calculate put price

Please help with the following problem. Include calculations. Suppose that the stock now sells at $80, and the price will go up by 5% or down by 5% at the end of first six month (t = ½). Then, the price will either go up by 10% or down by 10% at the end of year (t = 1). A call option on the stock has an exercise price of