How Do You Solve This Algebra Age Problem?

Question

(I can only use 1 variable)
Jim is now three times as old as Kathy. Four years ago, Jim was 7 times as old as Kathy was then. Find their present ages.

show all steps please! (show a table if used)

Answer 1

Sort of 1 variable. What you mean is you have 2 equations and 2 variables that you can combine to 1 eqautions and 1 variable

Jim = J Kathy = K

J = 3K and J-4 = 7(k-4)

So put 3k in for J in the second equation and solve

J-4 = 7(k-4)
3k-4= 7(k-4)
3k-4 = 7k-28
7k-3k= 28-4
4k = 24
k = 6

Kathy is 6, and Jim is 18. When Kathy was 2, Jim was 14