ming-li be 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 she have to begin with?

She began with $15.

Step-by-step explanation:

Let Ming-li has $x to spend.

She spent $15 at the movies.

Net balance = $ (x - 15)

She spent $12 at the book store.

Balance amount = $ (x - 15) - 12

She earned $30 by babysitting.

Net amount she had = $[x - 15 - 12 + 30]

= $ (x + 3)

She is now left with the total amount = $18

Therefore, the expression will represent the amount left will be

(x + 3) = 18

x = 18 - 3

x = $15

She began with $15.