The problem is "Given: A/B=7/9 and C/D=5/3; If B=4D, compute A+B/C+D". It's not homework, just a practice problem, so no rush (not that there would be anyway, but you know). I don't really understand how to start. I've tried a lot of things, basically just creating equations and substituted, but nothing has worked. I'd appreciate if someone could show me how to begin finding the variables. Thanks!