Step 1:
Step 2: 50% of 720 = = 360
10% of 720 = = 72
of 720) = = 31
Step 3: 360 + 72 – 31 = 401
Step 1: Olivia used percents that are not equivalent to 55%.
Step 2: Olivia incorrectly determined 50% of 720.
Step 2: Olivia incorrectly determined of 10% of 720.
Step 3: Olivia subtracted of 10% when she should have added.