SOLUTION: In 1921, Grandpa is 2 times older than Tom in 2000. In 1930, Grandpa is 3 times older than Tom in 2000. What is grandpa age in 2000? I'm not sure how to solve this but this is w

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Question 941090: In 1921, Grandpa is 2 times older than Tom in 2000. In 1930, Grandpa is 3 times older than Tom in 2000. What is grandpa age in 2000?
I'm not sure how to solve this but this is what I did:
(G = Grandpa age)
2G=3(G+9) --> 2G=3G+27 -->G=+27 a.k.a G=27 (Age in 1930) -->(2000-1930)+27 = 97 years old in 2000
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = Tom's age in 2000
Let +g+ = grandpa's age in 2000
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In 1921, grandpa's age is +g+-+79+
( 2000 - 1921 = 79 )
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(1) +g+-+79+=+2t+
---------------------
In 1930, grandpa's age is +g+-+70+
( 2000 - 1930 = 70 )
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(2) +g+-+70+=+3t+
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(1) +t+=+%28+g+-+79+%29+%2F+2+
and
(2) +t+=+%28+g+-+70+%29+%2F+3+
-----------------------
+%28+g+-+79+%29+%2F+2+=+%28+g+-+70+%29+%2F+3+
Multiply both sides by +6+
+3%2A%28+g+-+79+%29+=+2%2A%28+g+-+70+%29+
+3g+-+237+=+2g+-+140+
+g+=+237+-+140+
+g+=+97+
grandpa is 97 in 2000
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check:
(1) +t+=+%28+g+-+79+%29+%2F+2+
(1) +t+=+%28+97+-+79+%29+%2F+2+
(1) +t+=+18%2F2+
(1) +t+=+9+
and
(2) +t+=+%28+g+-+70+%29+%2F+3+
(2) +t+=+%28+97+-+70+%29+%2F+3+
(2) +t+=+27%2F3+
(2) +t+=+9+
OK