SOLUTION: age of brother is twice than the age of sister,three years back age of brother was as three time as the age of the sister find the present ages and also show me that how to solve

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Question 872637: age of brother is twice than the age of sister,three years back age of brother was as three time as the age of the sister find the present ages and also show me
that how to solve it
Found 2 solutions by lwsshak3, josmiceli:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
age of brother is twice than the age of sister,three years back age of brother was as three time as the age of the sister find the present ages and also show me
that how to solve it
***
let x=present age of sister
2x=present age of brother
..
3 yrs ago:
x-3=age of sister
2x-3=age of brother
age of brother was three times the age of the sister
2x-3=3(x-3)
2x-3=3x-9
x=6
2x=12
present age of sister=6
present age of brother=12

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +b+ = brother's age now
Let +s+ = sister's age now
+b+-+3+ = brother's age 3 yrs ago
+s+-+3+ = sister's age 3 yrs ago
-------------------------------
(1) +b+=+2s+
(2) +b+-+3+=+3%2A%28+s+-+3+%29+
-------------------------
(2) +b+-+3+=+3s+-+9+
(2) +3s+-+b+=+6+
Substitute (1) into (2)
(2) +3s+-+2s+=+6+
(2) +s+=+6+
and, since
(1) +b+=+2s+
(1) +b+=+2%2A6+
(1) +b+=+12+
Brother is 12 and sister is 6
check:
(2) +b+-+3+=+3%2A%28+s+-+3+%29+
(2) +12+-+3+=+3%2A%28+6+-+3+%29+
(2) +9+=+3%2A3+
(2) +9+=+9+
OK