Question

A fair spinner has 12 equal sections: 4 red, 3 blue and 5 green. It is spun twice. What is the probability of getting the same colour twice?

Answer 1

25/72

Explanation:

Total outcomes :

• (5 + 4 + 3)²
• (12)²
• 144 outcomes

P (red twice) :

• 16/144
• 1/9

P (blue twice) :

• 9/144
• 1/16

P (green twice) :

• 25/144
• 5/12

Adding :

• 1/9 + 1/16 + 5/12
• 16/144 + 9/144 + 25/144
• 50/144
• 25/72