EXPLANATION :
From the problem, we have the fraction :
We need to find the common factor between the numerator and the denominator.
30 = 2 x 3 x 5
80 = 2 x 2 x 2 x 2 x 5
The common factor is 2 x 5 which is equal to 10.
Divide both numerator and denominator by 10 :
ANSWER :
The answer is B. 3/8