please do the problem on excel. and show your steps. thanks.

The 1 and 2 year spot rates are 2.42% and 3.92% respectively, and the expected interest rate volatility is 15.24%. You are building a two year binomial interest rate tree: Time 0 (%) Time 1 (%) i2h = i21'e (20) i1 = 2.42 i21 = ?? You must calibrate this tree such that the price of a 2 year zero coupon bond is correct using this tree (in other words, produces the same price as using the 2 year spot rate). What should be your i21 (the lower possible lyly forward rate) in your tree