Louis has m shirts , n trousers and r caps , show that Louis has m × n × r different outfit combination without using a tree diagram.

Question

How?

Answer 1

draw a tree
there are m branches on the first level
for each of those nodes, draw n branches for trousers.
On the 3rd level, draw r branches for each trousers node

I mean, how else can a tree look?

Answer 2

They said without a tree diagram