Question

The ratio of two numbers is 7 to 5. The sum of the numbers is 36. What are the numbers?

Answer 1

let the two numbers be 7x and 5x
7x + 5x = 36
12x = 36
dividing both sides by 12
x = 3
two numbers are 7*3 = 21
5*3 = 15

Answer 2

Sheg's answer is more efficient than mine, but here's another way to see it:

"The ratio of two numbers is 7 to 5" translated into math language is\[{x \over y}={7\over5}\]"The sum of the numbers is 36" translates as\[x+y=36\]2 equations+2 unknowns=A solvable problem!

Sheg has provided the answer :)