One number is one-fifth of another number. the two numbers total 18. find the numbers

One number is 17 and the other is 85.

Step-by-step explanation:

Let the numbers be m and n.  Let m = (1/5)n.  Note that m+n = 18.

Substituting (1/5)n for m in the 2nd equation, we get (1/5)n + (5/5)n = 18.  Multiplying all three terms by 5 to remove fractions, we get n + 5 = 90, so that n = 85.  m is (1/5) of 85, or m = 17.

$12. that is my answer.