SOLUTION: two years ago my dad was twice my age. 13 years ago my dad's age was trip;e mine. how old am i now

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Question 1044763: two years ago my dad was twice my age. 13 years ago my dad's age was trip;e mine. how old am i now
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = my age now
+a+-+2+ = my age 2 years ago
+a+-+13+ = my age 13 yrs ago
Let +b+ = my dad's age now
+b+-+2+ = my dad's age 2 yrs ago
+b+-+13+ = my dad's age 13 yrs ago
------------------------------------
(1) +b+-+2+=+2%2A%28+a+-+2+%29+
(2) +b+-+13+=+3%2A%28+a+-+13+%29+
--------------------------
(1) +b+-+2+=+2a+-+4+
(1) +2a+-+b+=+2+
and
{2} +b+-+13+=+3%2A%28+a+-+13+%29+
(2) +b+-+13+=+3a+-+39+
(2) +3a+-+b+=+26+
----------------------------
Subtract (1) from (2)
(2) +3a+-+b+=+26+
(1) +-2a+%2B+b+=+-2+
--------------------
+a+=+24+
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I am 24 now
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check answer:
(1) +b+-+2+=+2%2A%28+a+-+2+%29+
(1) +b+-+2+=+2%2A%28+24+-+2+%29+
(1) +b+=+2%2A22+%2B+2+
(1) +b+=+46+
and
(2) +b+-+13+=+3%2A%28+a+-+13+%29+
(2) +b+-+13+=+3%2A%28+24+-+13+%29+
(2) +b+=+3%2A11+%2B+13+
(2) +b+=+46+
OK