📌 Step 1: Identify the condition
"Given that a student prefers Math" means we only look at the Math column.

📌 Step 2: Find the relevant numbers
Total who prefer Math = 30
10th graders who prefer Math = 12

📌 Step 3: Calculate conditional probability
P(10th | Math) = 12/30 = 2/5 = 0.40 = 40%

💡 Key concept: Conditional probability restricts the sample space. We're not looking at all 60 students — only the 30 who prefer Math.