Answer:
She bought 10 chocolate doughnuts.
Explanation:
Mrs. Santiago is buying doughnuts for her office.
Each box contains 4 cream filled doughnuts.
She bought 20 total cream filled doughnuts.
Number of boxes which contains 20 cream filled doughnuts =
= 5 boxes
There are 2 chocolate flavored doughnuts in each boxes, so she bought chocolate flavored doughnuts = 5 × 2 = 10
She bought 10 chocolate doughnuts.