Compound A contains 1.75g nitrogen and 3.99g oxygen. Compound B contains 19.6g nitrogen and 56.0g oxygen. Are compounds A and B the same? Explain.

You can do it the hard way;

1. Calculate percent N and percent O, then take 100 g sample, change to moles, and from there the empirical formula for NxOy.

2. Or you can try a simpler method.
Set up ratio/proportion.
(19.6/1.75)=(x/3.99) . Solve for x and see if it is the same as stated in the problem. Make sure I set that proportion up correctly.