Choice D is the correct answer. Let $s$ be the number of student tickets and $a$ be the number of adult tickets.

Given: $s = 5$ and $10s + 15a = 95$

Step 1: Substitute $s = 5$: $10(5) + 15a = 95$$50 + 15a = 95$

Step 2: Solve for $a$: $15a = 45$$a = 3$

Solution: 3 adult tickets were sold.

Verification: $10(5) + 15(3) = 50 + 45 = 95$ ✓

💡 Strategic Tip: When one variable is given, substitute immediately to simplify.

Choice A is incorrect because$10(5) + 15(2) = 50 + 30 = 80 \ eq 95$.

Choice B is incorrect because$10(5) + 15(4) = 50 + 60 = 110 \ eq 95$.

Choice C is incorrect because$10(5) + 15(5) = 50 + 75 = 125 \ eq 95$.