Answer :
The number of masks that Mayerlin kept on her wall given the information in the question is 304.
What are percentages?
Percentage is the fraction of an amount that is usually expressed as a number out of hundred. Percentages are a measure of frequency.
How many masks are on the wall?
Percentage of the masks on the wall = 100 - 24 = 76%
Number of the masks on the wall = 76% x 400 = 304
To learn more about percentages, please check: https://brainly.com/question/25764815