Ou need to put your reindeer, Quentin, Jebediah, Lancer, and Gloopin, in a single-file line to pull your sleigh. However, Gloopin and Lancer are fighting, so you have to keep them apart, or they won't fly. How many ways can you arrange your reindeer?

Respuesta :

NickRM

Answer:

12

assume 2 and 4 are glooping and lancer.

1234 1432

2134 2314 2341 2143

3214 3412

4123 4321 4312 4132

you see when glooper and lancer are not at the front, there are only two combinations. When glooper and lancer are at the front, there are 4 possible combinations.