The following question has three statements. Study the question and the statements and decide which of the statement (s) is/are necessary to answer the question.
How many students are studying biology?
I. The number of students studying biology and zoology presently in ratio 5: 8respectively
II. The number of students studying zoology this year and that last year is 8: 9 respectively.
III. The number of students who studied biology in the last year was 200
1
Only statement I alone sufficient to answer the question
2
Only statement II alone answer the question
3
Only statement III alone sufficient to answer the question
4
All I,II, and III necessary to answer the question
5
None of these