The table shows the distribution of marks scored by students in a test.

Mark (%)	10 - 19	20 - 29	30 - 39	40 - 49	50 - 59	60 - 69	70 - 79	80 - 89	90 - 99
Frequency	4	7	12	18	20	14	9	4	2

(a) Construct a cumulative frequency table for the distribution.

 

(b) Draw a cumulative frequency curve for the distribution.

 

(c) Use the curve to estimate the:

(i) median;

(ii) probability that a student selected at random obtained distinction, if the lowest mark for distinction is 75%.