Question

There are 3 black balls, 4 blue balls and 5 red balls in a box. In how many ways can we choose 3 balls at the same time with different colors? 

Answer 1

Taking into account that there are 3 black balls, 4 blue balls and 5 red balls in a box, we conclude by Combinatorial Product Rule that the number of ways we can choose 3 balls at the same time with different colors is equal to $3\cdot 4\cdot 5=60.$