Question

http://imageshack.us/photo/my-images/502/12698272.jpg/

This is a cumulative frequency graph which is in link. From the graph I managed to estimate the median mark,the inter-quartile range and the passing mark if three-fifths of the students passed. But I couldn't find the number of students achieving more than 0 marks.



Median mark=32

Inter-quartile range= 15

Pass mark if three-fifths of the students passed=28

The number of students achieving more than o marks= ??