Question

one number is chosen at random from the set {3, 5, 6, 7, 9, 15, 20, 35}. find the chance of choosing: (a) an even number 15% 25% 33% 40%

Explanation:

Step1: Count total numbers

Total elements: $n(\text{total}) = 8$

Step2: Count even numbers

Even numbers: {6,20}, so $n(\text{even}) = 2$

Step3: Calculate probability

Probability: $\frac{n(\text{even})}{n(\text{total})} = \frac{2}{8} = 0.25$

Step4: Convert to percentage

Percentage: $0.25 \times 100\% = 25\%$

Answer:

25%