Question

Question #b13c2

Answer 1

Let's call them A1, A2, A3 for maths, B1, B2 for physics, and C1, C2 for philosophy.

Explanation:

Within the groups there are 6 posibilities for the A-group:
123, 132, 213, 231, 312, 321
For the other groups there are only 1,2 and 2,1.

The groups themselves can be ordered in 6 ways (as for any 3 items).

For the total number of orders we multiply all possibilities:

`N=6xx6xx2xx2=144`

Extra : the total number of orders if groups don't have to stay together is: `7xx6xx5xx4xx3xx2xx1=7! =5040`