Question

You are thinking of using some leftover ceramic tiles to make a decorative border for a patio. You have ten blue, four gold, and six white tiles. In how many ways can you make the border if it requires 15 tiles and you use only blue and white ones? Explain your reasoning.
i need help on this question

Answer 1

number of ways to choose:
6W,9B
5W,10B

Number of ways to arrange 6W,9B = (15!/6!9!) = 5005
number of ways to arrange 5W,10B = 15!/(5!10!) = 3003

total number of ways = 5005+3003 = 8008