hi guys question : Compute the lowest possible price for a 3months American and European 65calls on a stock that is trading at 68 when RFR is 5% using the formula S-X/(1+RFR)to the power of T when ever i use the calculator i get $2.96 but the correct answer is $3.96 i thought i was doing some thing on the calculator but i tried in on a different calculator. any suggestions

scratch that i figured it out too late at night i need more coffee

The solution is: Min call: S - [X/(1+rfr)^0.25]= 68 - [65/(1,05)^0.25]