I think it is 4 1/8. Sorry If I am wrong, just trying to help.
So we are using the denominator 20.
1/2 of 20 would be 10.
So, out of 20 we multiply it by 10 since it is our numerator.
Now, we have converted it to 100/200.
Freshman : 100 students
Sophomores : 10 students
Juniors : 20 students
Seniors : 70 students
L +2w = 500
a = lw
a) l = 500 -2w
.. a = (500 -2w)*w
b) The zeros of the above equation are w=0, w=250. The vertex of this quadratic is on the line of symmetry, halftway between the zeros, at w=125 ft.
c) a = (500 -2*125)*125 = 31,250 . . . . square feet
