SOLUTION: When Lisa was born, her dad was 26 years old. Now he is 3 times her age. How old is Lisa?

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Question 691635: When Lisa was born, her dad was 26 years old. Now he is 3 times her age. How old is Lisa?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The difference in their ages always
stays the same ( 26 yrs )
Let +a+ = Dad's age
Let +b+ = Lisa's age
+a+=+3b+
+a+-+b+=+26+
-------------
By substitution:
+3b+-+b+=+26+
+2b+=+26+
+b+=+13+
and
Lisa is 13
check answer:
+3b+=+39+
+a++=+3b+
+a+=+39+
+39+-+13+=+26+
OK