If I give my brother 5 dollars, then we will have the same amount of money. If instead, he gives me 12 dollars, then I'll have twice as much money as he will have. How much money does my brother currently have (in dollars)?
y = your amount
b = bro's amount
y-5 = b + 5
and
y +12 = 2 ( b-12)
y = 2b - 36 <===== sub into first equation
2b-36 -5 = b + 5
b = $ 46 y = 56