9514 1404 393
Answer:
20%
Step-by-step explanation:
100 mL of the drink is coffee
The total amount of drink is 100 mL +400 mL = 500 mL. Then the fraction that is coffee is ...
coffee/total = (100 mL)/(500 mL) = 1/5 = 1/5 × 100% = 20%
20% of Donna's drink is coffee.
