Chapter 11 Practice Paper: Probability of Single Events — mark scheme (print)

QuizQuipPractice Series

QQ/S2MATH/CH11

Secondary 2 · Lower Secondary Mathematics (G2 / G3)

Mark scheme

Probability of Single Events

Chapter 11 Practice Paper · Maximum mark: 30

Notes for markers

Award one mark for each point marked [1], up to the marks shown for the part.
Accept answers worded differently that show the same understanding.
Units are required where the answer line shows one. ecf: allow an error carried forward.

Section A: Multiple-choice questions[10 marks]

Question	Answer
1	DImpossible events sit at the very bottom of the scale: 0.	1
2	BFour kings out of 52 cards: 4/52 = 1/13.	1
3	CThree evens (2, 4, 6) out of six: 3/6 = 1/2.	1
4	A26 of the 52 cards are hearts or spades: 26/52 = 1/2.	1
5	BThe odds are 1, 3, 5: three of the five outcomes.	1
6	DThe complement: 1 − 0.3 = 0.7.	1
7	C21 ÷ 60 = 0.35.	1
8	A0.25 × 80 = 20.	1
9	B7/8 sits inside the scale; the others leak outside [0, 1].	1
10	DSomething must happen, so the whole sample space totals 1.	1

Section B: Structured questions[20 marks]

Question	Answer and marking points	Marks
1(a)	{1, 2, 3, 4, 5, 6}. All six outcomes [1]	1
1(b)	Primes are 2, 3, 5: P = 3/6 = 1/2. Primes 2, 3, 5 counted [1] 1/2 [1]	2
1(c)	1 − 1/2 = 1/2 [1]	1
1(d)	Squares are 1 and 4: 2/6 = 1/3 [1]	1
	Total for Question 1	5
2(a)	5/10 = 1/2 [1]	1
2(b)	2/10 = 1/5 [1]	1
2(c)	P(blue) = 3/10, so P(not blue) = 1 − 3/10 = 7/10. P(blue) = 3/10 found [1] 7/10 [1]	2
2(d)	3/10 × 40 = 12 [1]	1
	Total for Question 2	5
3(a)	34 ÷ 200 = 0.17. 34 ÷ 200 used [1] 0.17 [1]	2
3(b)	0.17 [1]	1
3(c)	0.17 × 60 = 10.2, so about 10 days. 0.17 × 60 used [1] About 10 days [1]	2
	Total for Question 3	5
4(a)	2/11 [1]	1
4(b)	Vowels are A, E, A, I: 4 of 11, so P = 4/11. Four vowels counted [1] 4/11 [1]	2
4(c)	1/11 [1]	1
4(d)	1 − 4/11 = 7/11 [1]	1
	Total for Question 4	5

— End of mark scheme —