Notice that 4 divided by itself equals one. So if you take 4 times one, it equals 4. Do the same to the 2, multiplying it by 4 making 8. It would be 8 over 4. Add the 2 zeros to the 4 and the 1 making 2/100 and 8/400.
So you have 2/100 and x/400. To solve, you must first do cross multiplication. That means you multiply x by 100 and 2 by 400. You will get 100x=800. You then simplify the equation to find out that x=8.
