In two successive years, 100 and 75 students of a school appeared at the final examination. Respectively 75 % and 60 % of them passed. The average rate of pass is:_________?

A. 68 4/7 %
B. 78 %
C. 80 %
D. 80 4/7 %
Explanation:
Total candidates = (100 + 75) = 175
Total passed = (75/100 × 100) + (60/100 × 75)
= (75 + 45) = 120
Therefore Pass % = (120/175 × 100)%
= 480/7 % = 68 4/7 %