Jerrys train has 4cars of different colors yellow green red and blue. How many different ways can Jerry arrange his train cars

Answer 1

Assuming the train will consist of 4 cars, and he has one car of each of the four colors Y, G, R and B (total 4 cars)

The 1st car has 4 color possibilities, the 2nd car has 3 possibilities, (one car is already assigned to the 1st position), 3rd car has 2 possibilities and finally only one color left for the 4th car. Answer is 4 x 3 x 2 x 1 = 24 possible train configurations. [Same as 4 factorial (4!) or 4P4, (the number of permutations of 4 items taken 4 at a time)].