Printable · GCSE Foundation · ages 14-16

Independent and dependent combined events worksheet — GCSE Foundation

Fifteen questions on "independent and dependent combined events" — DfE statement P8. Print it, or print three versions so neighbours cannot copy by letter; the key gives the letter for each version.

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Independent and dependent combined events worksheet — GCSE Foundation

Maths · GCSE Foundation · P8 · Independent and dependent combined events · Non-calculator · 15 questions

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1.Five raffle tickets numbered 1 to 5 are in a bag. Two tickets are drawn one after the other and the first is not put back. Work out the probability that ticket 1 is drawn first and ticket 2 is drawn second.
(a)1/25
(b)1/20
(c)2/5
(d)1/10
2.A drawer contains 4 red socks and 2 blue socks. Two socks are taken out at random, one after the other, without the first being put back. Work out the probability that both socks are the same colour.
(a)7/18
(b)2/5
(c)5/9
(d)7/15
3.A fair spinner has 8 equal sections: 5 are red and 3 are blue. Freya spins it twice, and each spin is independent of the other. Work out the probability that she gets one red and one blue in the two spins, in either order.
(a)39/64
(b)15/32
(c)15/28
(d)15/64
4.Two events are independent. The first has probability 2/5 and the second has probability 1/3. Work out the probability that both events happen.
(a)1/15
(b)11/15
(c)2/15
(d)3/8
5.A tree diagram shows two rounds of a game, played independently. On each round, the probability of losing is 0.7 and the probability of winning is 0.3. Work out the probability of losing both rounds.
(a)0.09
(b)1.4
(c)0.49
(d)0.7
6.The probability that Ben catches his bus on time is 0.8. The probability that Freya catches her bus on time is 0.5. The two events are independent. Work out the probability that both Ben and Freya catch their bus on time.
(a)0.3
(b)0.4
(c)1.3
(d)0.1
7.A fair coin is flipped three times. Work out the probability of getting at least one head.
(a)1/2
(b)1/8
(c)7/8
(d)3/8
8.A spinner has equal sections, and the probability that it lands on blue in a single spin is 1/4. It is spun twice, and the two spins are independent. Work out the probability that it lands on blue on both spins.
(a)1/16
(b)1/2
(c)1/4
(d)1/8
9.Two ordinary fair dice are rolled, one after the other. Work out the probability that the first dice shows a 6 and the second dice shows an even number.
(a)1/12
(b)1/36
(c)1/6
(d)1/2
10.An ordinary fair dice is rolled twice. Work out the probability of getting at least one 5.
(a)30/36
(b)11/36
(c)25/36
(d)12/36
11.The probability that Isla answers a quiz question correctly is 0.8. She answers three questions, and her answers are independent of each other. Work out the probability that she answers all three correctly.
(a)0.0512
(b)0.8
(c)0.512
(d)0.64
12.A fair spinner is divided into 5 equal sections, 2 labelled win and 3 labelled lose. Zara spins it twice, and the two spins are independent. Work out the probability that she wins on the first spin and loses on the second spin.
(a)9/25
(b)6/25
(c)4/25
(d)3/10
13.A bag contains 5 letter tiles spelling the word MATHS, with one letter on each tile. Two tiles are drawn at random, one after the other, without the first tile being put back. Work out the probability that both tiles drawn are consonants.
(a)3/4
(b)4/5
(c)16/25
(d)3/5
14.The probability that a component is faulty is 1/10. Two components are tested independently. Work out the probability that at least one of the two components is faulty.
(a)1/5
(b)1/10
(c)1/100
(d)19/100
15.In Manchester the probability of rain on any day in November is taken to be 0.3, and whether it rains on one day is independent of whether it rains on the next. Work out the probability that it rains on both the 10th and the 11th of November.
(a)0.09
(b)0.6
(c)0.9
(d)0.3

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