The table below shows the marks obtained by forty pupils in a Mathematics test.

Marks	0 - 9	10 - 19	20 - 29	30 - 39	40 - 49	50 - 59
No of pupils	4	5	6	12	8	5

(a) Draw a histogram for the mark distribution ;

(b) Use your histogram to estimate the mode ;

(c) Calculate the median of the distribution.