[Aditya]

Both the parts can be solved by middle term splitting method.

(1) m^2 – 23m + 120 = 0

m^2 – 15m -8m +120 = 0

m(m – 15) – 8(m – 15) = 0

(m-15)*(m-8) = 0 -> Answer

(2) 3m^2 + 14m + 15 = 0

3m^2 + 9m + 5m + 15 = 0

3m(m + 3) + 5(m + 3) = 0

(3m + 5)*(m + 3) = 0 -> Answer

[Aditya]

Answer : Equal fraction of students passed first class.

Solution :

Fraction of students passing first class for class A = 20 / 25 = (4 / 5)

Fraction of students passing first class for class B = 24 / 30 = (4 / 5)

Since both fractions are equal, equal fraction of students passed first class