SOLUTION: Samuel is 1/2 as old as his brother. In seven years, he will be 2/3 as old as his brother will be. Find their present ages.

Algebra ->  Customizable Word Problem Solvers  -> Age -> SOLUTION: Samuel is 1/2 as old as his brother. In seven years, he will be 2/3 as old as his brother will be. Find their present ages.       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 984046: Samuel is 1/2 as old as his brother. In seven years, he will be 2/3 as old as his brother will be. Find their present ages.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let s+ = Samuel's age now
Let +b+ = brother's age now
(1) +s+=+%281%2F2%29%2Ab+
(2) +s+%2B+7+=+%282%2F3%29%2A%28+b+%2B+7+%29+
---------------------------
substitute (1) into (2)
(2) +%281%2F2%29%2Ab+%2B+7+=+%282%2F3%29%2A%28+b+%2B+7+%29+
Multiply both sides by +6+
(2) +3b+%2B+42+=+4%2A%28+b+%2B+7+%29+
(2) +3b+%2B+42+=+4b+%2B+28+
(2) +b+=+42+-+28+
(2) +b+=+14+
and
(1) +s+=+%281%2F2%29%2A14+
(1) +s+=+7+
Samuel is 7
His brother is 14
-----------------
check:
(2) +s+%2B+7+=+%282%2F3%29%2A%28+b+%2B+7+%29+
(2) +7+%2B+7+=+%282%2F3%29%2A%28+14+%2B+7+%29+
(2) +14+=+%282%2F3%29%2A21+
(2) +42+=+2%2A21+
(2) +42+=+42+
OK