Using proportions, it is found that since 43% of the total amount is 129, 300 students were surveyed in total.
A proportion is a fraction of a total amount.
In this problem, since 57% of the students surveyed said their favorite color was blue, hence 100 - 57 = 43% said it was red, and this amount is of 129 students, hence:
0.43n = 129
n = 129/0.43.
n = 300.
300 students were surveyed in total.
More can be learned about proportions at https://brainly.com/question/27396612
