SOLUTION: Ten years ago, benjamin was 3 times as old as tofer,in 7 years, benjamin will be twice as old as tofer. How old is he now?

Algebra ->  Human-and-algebraic-language -> SOLUTION: Ten years ago, benjamin was 3 times as old as tofer,in 7 years, benjamin will be twice as old as tofer. How old is he now?      Log On


   



Question 1066383: Ten years ago, benjamin was 3 times as old as tofer,in 7 years, benjamin will be twice as old as tofer. How old is he now?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +b+ = Benjamin's age now
Let +t+ = Tofer's age now
-------------------------------
(1) +b+-+10+=+3%2A%28+t+-+10+%29+
(2) +b+%2B+7+=+2%2A%28+t+%2B+7+%29+
-------------------------------
(1) +b+-+10+=+3t+-+30+
(1) +3t+-+b+=+20+
and
(2) +b+%2B+7+=+2t+%2B+14+
(2) +-2t+%2B+b+=+7+
-------------------------------
Add (1) and (2)
(1) +3t+-+b+=+20+
(2) +-2t+%2B+b+=+7+
--------------------
+t+=+27+
and
(1) +3t+-+b+=+20+
(1) +3%2A27+-+b+=+20+
(1) +81+-+b+=+20+
(1) +b+=+81+-+20+
(1) +b+=+61+
Benjamin is 61 now
-------------------------
check:
(1) +b+-+10+=+3%2A%28+t+-+10+%29+
(1) +61+-+10+=+3%2A%28+27+-+10+%29+
(1) +51+=+3%2A17+
(1) +51+=+51+
You can check (2)