Answer:
60% of her students brought something for Mrs. Nguyen on her birthday.
Explanation:
She has 25 students in her class.
12 gave her cards.
2 gave her flowers.
1 gave her chocolates.
Add them together to get 12+2+1=15.
15 students out of 25 can also be written as a fraction:
This equals 0.6 as a decimal. To find the percentage multiply by 100, to get 60. Therefore 60% of her students got something for her.