Explanation:
Mrs. Lopez deposited $1,200 in her savings account at the beginning of the summer. This was the initial amount.
She withdrew 700 in June and 450 in July for her trips. And we have to find the money left with Mrs. Lopez i.e. Total money she had with her in the beginning - Money she withdraw

= 1200 - (700 + 450)
= 1200 - 1150
= 50
~Mrs Lopez was left with $50 in the end.