A stock price is currently $50. It is known that at the end of six months that the stock price will either increase or decrease by 9%. The risk-free interest rate is 6% per annum with continuous compounding. What is the value of a six-month European put option with a strike price of $51?

Equations you may find helpful:

p = (e^(rt)-d) / (u-d)

f = e^(-rt) * (fu*p + fd*(1-p)) (required precision 0.01 +/- 0.01)