Answer:
96 different codes are possible.
Explanation:
- First, we have to select two DIFFERENT symbols from X.
This can be done in 3 x 2 = 6 different ways (first we have 3 options and then we have 2 options)
- Secondly we need to select two not necessarily different symbols from Y.
This can be done in 4² = 16 different ways (first we have 4 options and because we can repeat symbols, we have other 4 options for our second choice)
- The total amount of symbols is found by multiplying both numbers since we have to choose 2 symbols from set X AND 2 from set Y
6 x 16 = 96 different codes are possible.