There are 70 students in the school band. 40% of them are sixth graders, 20% are seventh graders, and the rest are eighth graders. How many students are sixth graders?

Candice uses the function f(t)=t+100−−−−−−√ to model the number of students in her after-school program. the variable t represents days and f(t) represents the number of students. how many days does it take for there to be 15 students in her program? a. 225 days b. 125 days c. 325 days d. 115 days