1. The math fact completion rate for each student is:
Kiara: m = 5t, where t represents the time in seconds, and m represents the number of math facts completed. Therefore, Kiara's math fact completion rate is 5 math facts per second.
Giovanni: Giovanni's math fact completion rate is 4 math facts per second.
Ebony: Ebony's math fact completion rate is 12 math facts per second.
2. Ebony would win the argument, as she has the highest math fact completion rate.