Printable · GCSE Higher · ages 14-16

Independent and dependent combined events worksheet — GCSE Higher

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 Higher

Maths · GCSE Higher · P8 · Independent and dependent combined events · 15 questions

MathsUKwww.geekhero.co.uk

1.A bag contains 5 red counters and 5 green counters. Three counters are taken out one at a time and are not put back. Work out the probability that all three counters are red.
(a)1/12
(b)3/50
(c)1/8
(d)2/9
2.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
3.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
4.The probability that Leo wakes up before his alarm is 0.35. The probability that his younger sister wakes up before her alarm, independently of Leo, is 0.28. Work out the probability that neither of them wakes up before their alarm.
(a)0.098
(b)0.63
(c)0.532
(d)0.468
5.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
6.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
7.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
8.A bag contains 3 yellow counters and 2 green counters. Sophie takes one counter at random and does not put it back. She then takes a second counter at random. Work out the probability that the first counter is yellow and the second is green.
(a)3/20
(b)3/10
(c)3/5
(d)6/25
9.The probability that Kofi passes his driving test on any attempt is 0.6, and each attempt is independent of the others. Work out the probability that he fails both his first two attempts.
(a)0.16
(b)0.36
(c)0.24
(d)0.4
10.Two cards are dealt one after the other from an ordinary pack of 52 playing cards. The first card is not put back before the second is dealt. The pack contains 4 aces. Work out the probability that neither card is an ace. Give your answer as a product of two fractions.
(a)(4/52) × (3/51)
(b)(48/52) × (47/51)
(c)(4/52) × (4/51)
(d)(48/52) × (48/52)
11.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
12.The probability that a seed fails to germinate is 1/5. Three seeds are planted independently. Work out the probability that at least one of the three seeds germinates.
(a)12/125
(b)4/5
(c)64/125
(d)124/125
13.Harry plays a game in which he flips a fair coin and rolls an ordinary fair dice. He wins a prize only if the coin shows heads and the dice shows a 6. Work out the probability that Harry wins a prize.
(a)2/3
(b)1/12
(c)1/6
(d)1/8
14.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
15.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

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