O-Level Mathematics 3 — Questions and Answers
Question 1: What is the interior angle of a regular hexagon?
- 108°
- 120° (Correct answer)
- 135°
- 140°
Correct answer: 120°
Sum of interior angles = (6-2)×180° = 720°. Each angle = 720°÷6 = 120°.
Question 2: Expand and simplify: (x+3)(x-2)
- x²+x-6 (Correct answer)
- x²-x-6
- x²+x+6
- x²-x+6
Correct answer: x²+x-6
(x+3)(x-2) = x²-2x+3x-6 = x²+x-6.
Question 3: A bag contains 3 red and 5 blue balls. What is the probability of picking a red ball?
- 3/5
- 3/8 (Correct answer)
- 5/8
- 1/3
Correct answer: 3/8
P(red) = 3/(3+5) = 3/8.
Question 4: What is the HCF of 36 and 48?
- 6
- 12 (Correct answer)
- 18
- 24
Correct answer: 12
Factors of 36: 1,2,3,4,6,9,12,18,36. Factors of 48: 1,2,3,4,6,8,12,16,24,48. HCF = 12.
Question 5: Simplify: √75
- 5√3 (Correct answer)
- 3√5
- 5√5
- 3√3
Correct answer: 5√3
√75 = √(25×3) = 5√3.
Question 6: The price of an item increases from $80 to $92. What is the percentage increase?
- 12%
- 13%
- 15% (Correct answer)
- 10%
Correct answer: 15%
Increase = 12. % increase = (12/80) × 100 = 15%.
O-Level Mathematics 3
What is the interior angle of a regular hexagon?