Your small business is considering purchasing one of two different computers. Computer A costs $1,160 today and will increase after-tax revenues by $136 , $400 , and $1,223 over years 1-3 respectively. Computer B costs $990 today and will increase after-tax revenues by $677 , $386 , and $147 over years 1-3 respectively. If your firm's financing rate is 15%, what is the cross over rate between these two computers and which should you choose?

please explain well. no excel please