Ms.Grivers graded 10 of her students' assignments in 25 minutes. How long will it take her to grade the rest of her 110 students' assignments?

Use a simple ratio:

t/110 = 25/10
t = 110(25/10) = 275 minutes

or

10 students took 25 minutes
1 student took 25/10 minutes,
so 110 students took 110(25/10) minutes = 275 minutes