okay back to the Bill and Sally question I posted several times yesterday, can anyone give me an algebraic break down of exactly how to solve this trick question?
Bill and Sallys age totals 28 .Bill is 20 years older than Sally , how old is Sally?

Question

anonymous · Answer

Very Good!Your the first to break this down so well!

anonymous · Answer

Bill ->B
Sallys->S

B+S=28   (1)
B=S+20   (2)

replacing (2) in (1) thus

(S+20) + S=28

2S=8
S=4

anonymous · Answer

=)