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)$68 \frac{4}{7} \%$
(b)78\%
(c)80\%
(d)$80 \frac{1}{2} \%$
Answer
Answer (as printed): A
Explanation
Total number of students $=(100+75)=175$. Number of students passed = 75\% of 100 + 60\% of 75 $$\text { = } 75+45=120 . \text { ∴ Pass percentage }=\left(\frac{120}{175} \times 100\right) \%=\left(\frac{480}{7}\right) \%=68 \frac{4}{7} \% .$$
Explanation as extracted from the printed page; notation may be imperfect.