Susy had 2/3 as much money as Mary at first. After receiving 1/2 of Mary's money, Susy had $210. How much money did Susy have at first
susy: x
mary: y
x=2/3y
x+1/2y=210
therefore
2/3y+1/2y=210
4/6y+3/6y=210
7/6y=210
y=180 (Mary)
x=180*2/3=120 (Susy)
easy peazy
