SOLUTION: A woman is now 30 years older than her son. 15 years ago,she was twice as old. What are the present ages of the woman and her son

Algebra ->  Human-and-algebraic-language -> SOLUTION: A woman is now 30 years older than her son. 15 years ago,she was twice as old. What are the present ages of the woman and her son      Log On


   

Question 1104122: A woman is now 30 years older than her son. 15 years ago,she was twice as old. What are the present ages of the woman and her son
Found 3 solutions by josmiceli, josgarithmetic, Alan3354:
Answer by josmiceli(19441) About Me  (Show Source):
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Let +a+ = present age of the woman
Let +b+ = present age of her son
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(1) +a+=+b+%2B+30+
(2) +a+-+15+=+2%2A%28+b+-+15+%29+
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(2) +a+-+15+=+2b+-+30+
(2) +-a+%2B+2b+=+15+
and
(1) +a+-+b+=+30+
Add (1) and (2)
+b+=+45+
and
(1) +a+=+b+%2B+30+
(1) +a+=+45+%2B+30+
(1) +a+=+75+
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The woman is 75
Her son is 45
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check:
(2) +a+-+15+=+2%2A%28+b+-+15+%29+
(2) +75+-+15+=+2%2A%28+45+-+15+%29+
(2) +60+=+2%2A30+
(2) +60+=+60+
OK

Answer by josgarithmetic(39617) About Me  (Show Source):
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w, woman
y, son
system%28w=y%2B30%2Cw-15=2%28y-15%29%29

y%2B30-15=2y-30
30-15%2B30=y
highlight%28y=45%29, the son now
-
highlight%28w=75%29, the woman now

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
A woman is now 30 years older than her son. 15 years ago,she was twice as old. What are the present ages of the woman and her son
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The age difference is constant = 30 years.
--> she was 2x his age at 30 & 60
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"present age" is redundant. Just "age" is sufficient.
It's similar to "where are you now?" --> Where are you?