SOLUTION: "you were a quarter of my age when I was twice your present age" said A to B. In five years from now, our ages will add upto 45. how old was I when you were born? {A is asking B}

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Question 519498: "you were a quarter of my age when I was twice your present age" said A to B. In five years from now, our ages will add upto 45. how old was I when you were born? {A is asking B}
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let a = A's age now
Let b = B's age now
given:
+a+%2B+5+%2B+b+%2B+5+=+45+
+a+%2B+b+=+35+
The difference in their ages is
always +a-b+ (assuming a is older)
When a+=++2b+, then B
must have been +2b+-+%28a-b%29+=+3b+-+a+
+3b+-+a+=+%281%2F4%29%2A2b+
+3b+-+a+=+%281%2F2%29%2Ab+
+6b+-+2a+=+b+
+5b+=+2a+
+b+=+%282%2F5%29%2Aa+
and
+a+%2B+b+=+35+
+a+%2B+%282%2F5%29%2Aa+=+35+
+5a+%2B+2a+=+175+
+7a+=+175+
+a+=+25+
and, since
+a+%2B+b+=+35+
+b+=+10+
When B was born ( age = 0 )
The difference in their ages was +15+
so A was +15+ answer
-----------------
check answer:
In 5 years, their ages will add up to +45+
+10+%2B+5+%2B++25+%2B+5+=+45+
+45+=+45+
OK
When A was +2b+=+20+,
B was +20+-+15+=+5+
+5+ is 1/4 of +20+
OK