The table shows the scores of 2000 candidates in an entrance examination into a private secondary school.

% Mark	11-20	21-30	31-40	41-50	51-60	61-70	71-80	81-90
No of  pupils	68	184	294	402	480	310	164	98

(a) Prepare a cumulative frequency table and draw the cumulative frequency curve for the distribution.

(b) Use your curve to estimate the : (i) cut off mark, if 300 candidates are to be offered admission ; (ii) probability that a candidate picked at random, scored at least 45%.