To represent the situation where Demetrius can spend up to $50 on shirts that cost $16 each, we can use the variable \( s \) to represent the number of shirts he buys.
The total cost of the shirts can be expressed as \( 16s \) (since each shirt costs $16). We want to express the fact that this total cost should be less than or equal to the amount he can spend, which is $50.
Therefore, the inequality that represents this situation is:
\[ 16s \leq 50 \]