Question

Ming-Li spent $15 at the movies. She then earned $30 babysitting. She spent $12 at the bookstore. She now has $18 left. How much money did Ming-Li have to begin with?

Answer 1

X - 15 + 30 - 12 = 18;
Then x - 15 + 18 = 18;
x + 3 = 18;
x = $15 ( money has Ming-Li to begin with ).

Answer 2

X = original amount

x - 15 + 30 - 12 = 18
x + 30 - 27 = 18
x + 3 = 18
x = 18 - 3
x = 15 <== she began with 15