Answers

2015-07-26T13:45:08+05:30
Let the age of son be y
Now present age of son is 30,therefore present age of father is 30+20=50
Age before z years=30-z and 50-z
Now (30-z)2=(50-z)1
60-2z=50-z
60-50=-z+2z
ie,10=z
therefore it was 10 years before was their ages ratio 1:2 
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