A school has 4 section of Chemistry in Class X having 40, 35, 45 and 42 students. The mean marks obtained in Chemistry test are 50, 60, 55 and 45 respectively for the 4 sections. Determine the overall average of marks per student.	Choose the correct choice from the following
A) 50.25	B) 52.25	C) 51.25	D) 53.25	E) none of the above

Rationale: "required average marks = 40 × 50 + 35 × 60 + 45 × 55 + 42 × 45 / 40 + 35 + 45 + 42 = 2000 + 2100 + 2475 + 1890 / 162 = 8465 ⁄ 162 = 52.25 answer b"
Answer: B