Answer:
35 different ways
Explanation:
Since there are 7 students in a classroom to fill a front row containing 3 seats, we will apply the combination rule since we are to select 3 students from the total number of 7 students in the class.
In combination, if r objects are to be selected from a pool of n objects, this can be done in nCr number of ways.
nCr = n!/(n-r!)r!
Selecting 3 students from 7 students to fill the seats can therefore be done in 7C3 number of ways.
7C3 = 7!/(7-3)!3!
7C3 = 7!/(4)!3!
7C3 = 7*6*5*4!/4!*3*2
7C3 = 7*6*5/6
7C3 = 7*5
7C3 = 35
Hence there are 35 different ways that the student can sit in the front assuming there are no empty seats.