On a test consisting of 250 questions, Jassi answered 40\% of the first 125 questions correctly. What percent of the other 125 questions does she need to answer correctly for her grade on the entire exam to be 60\%?
(a)60
(b)75
(c)80
(d)Cannot be determined
(e)None of these
Answer
Answer (as printed): C
Explanation
Number of questions answered correctly $=40 \%$ of $125=50$. For 60\% grade, number of questions to be answered correctly $=60 \%$ of $250=150$. Remaining number of questions to be answered correctly $=150-50=100$. $$\text { ∴ } \text { Required percentage }=\left(\frac{100}{125} \times 100\right) \%=80 \% .$$
Explanation as extracted from the printed page; notation may be imperfect.