The ratio of two numbers is 7 to 5.the sum of the numbers is 36.what are the numbers? 18 and 18,
14 and 10
21 and 15
26 and 10

Let's say those numbers are "a" and "b"

so.. we know that a/b  are 7/5, whatever "a" and "b" may be

and we also know that their sum is 36, or  a + b = 36

thus   

solve for "b", to see what "b" is

what's "a"?   well