SOLUTION: Kathy is twice as old as Lisa. Three years from now, the sum of their ages will be 42. How old is Kathy? I would like it if you showed my step, by step how did you do it, I got

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Question 242932: Kathy is twice as old as Lisa. Three years from now, the sum of their ages will be 42. How old is Kathy?
I would like it if you showed my step, by step how did you do it, I got the answer 24 myself but I'm not completely sure how it did it
X = Kathy's age, 42/2 +3, and then i got 24...
but somehow, your suppose to write it like this: equation=42
Answer by JimboP1977(311) About Me  (Show Source):
You can put this solution on YOUR website!
Good to see you have had a good go at this problem!
Let K = Kathy's age and L=Lisa's age
K+=+2L
K%2B3%2BL%2B3+=+42
K%2BL%2B6+=+42
Subsitute K/2 in for L:
K%2B%28K%2F2%29%2B6+=42
K%2B%28K%2F2%29+=36
%282K%2BK%29%2F2+=36
3K%2F2+=+36
3K+=+72
K+=+24
Does that help? Make any sense?