exchange ratio and merger question

At the time America Online (AOL) announced plans to acquire Time Warner in January 2000, AOL stock was trading for $73.76 per share and Time Warner stock was trading for $65.69 per share. If the projected synergies were $40 billion, and Time Warner had 2.2 billion shares outstanding, what is the maximum exchange ratio AOL could offer in a stock swap and still generate a positive NPV? What is the maximum cash offer AOL could make