Alot of national flags are made up of three horizontal stripes.
how many different three colour flags (tricolors) can be designed using green, blue, red, yellow and black stripes if all three colours must be different?
how many of them contain a red stripe?
how many extra possibilities are there if the top colour can be the same as the bottom colour?
3 marks
on his university application, prashad must list his course choices in order of preference.

he must choose four of the six courses available in his major discipline and three of the four courses offered in related subjects.

in how many ways can prashad list his course choices? explain the reasoning for your answer.