How many students scored at least 40% marks in an exam?

Solution

Statement I: Number of students those secured 70% marks and above = 1/5 x 720 = 144 240 candidates have secured more than 20% but less than 40% marks in the exam. This statement alone is not sufficient to answer the question. Statement II: In this statement, we don’t have data about the number of students that secured 70 % and above marks. This statement alone is not sufficient to answer the question. On combining (I + II), Number of students those secured those less than 20% marks and those secured marks between 40% and 69% = 720 – 144 – 240 = 336 Number of students those secured between 40% and 69% = 2 x Number of students those secured less than 20% marks Number of students those secured between 40% and 69% = 2/3 x 336 = 224 So number of students those secured at least 40% marks = (40% to 69%) + (70% and above) = 224 + 144 = 368 Statement (I + II) together is sufficient to answer the question. Hence answer is option C