The table below shows the frequency distribution of the marks scored by fifty students in an examination.

Marks (%)	0-9	10-19	20-29	30-39	40-49	50-59	60-69	70-79	80-89	90-99
Freq	2	3	4	6	13	10	5	3	2	2

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

(b) Use your curve to estimate the : (i) upper quartile; (ii) pass mark if 60% of the students passed.