Under an employment promotion programme, it is proposed to allow sales of newspapers on the buses during off- peak hours. The vendor can purchase the newspaper at a (33)% special discounted rate per copy against the selling price of one Rial. Any unsold copies are, however a dead loss. A vendor has estimated the following probability distribution for the number of copies demanded.

No of copies demanded	20	21	22	23	24	25	26	27
Probability	0.1	0.12	0.15	0.17	0.17	0.2	0.06	0.03

How many copies should he order so that his expected profit will be maximum?