Probability worksheet — GCSE Foundation

1.A pupil must choose 2 different subjects at random from these five: maths, physics, biology, chemistry and history. Work out the probability that the two subjects chosen are maths and biology.

2.The probability that a machine completes a task successfully is 0.85. Work out the probability that the machine does not complete the task successfully.

3.A fair six-sided dice is rolled once. Work out the probability that the score is an odd number. Give your answer as a decimal.

4.The probability that Amelia's bus is late on a school morning is 9/10. Write this probability as a percentage.

5.A red fair dice and a blue fair dice are rolled together. Every outcome is listed as an ordered pair, red score then blue score. Work out the probability that the red score is less than the blue score.

6.A fair six-sided dice is rolled once. Write down the probability of rolling a 6.

7.Spinner A is numbered 1 to 3 and Spinner B is numbered 1 to 5. Both spinners are spun once, and every outcome is listed as a pair, one number from each spinner. Work out how many equally likely outcomes there are in total.

8.A survey of 60 readers records: 21 read only fiction, 17 read only non-fiction, 14 read both, and the rest read neither. Work out the probability that a randomly chosen reader reads exactly one of the two types, giving your answer as a fraction in its simplest form.

9.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.

10.The probability that a plant grown from a seed packet germinates is 7/10. Work out the probability that it does not germinate.

11.A survey of 90 people records which of two apps, X and Y, they use. 55 people use app X, 42 people use app Y, and 20 people use neither app. Work out the probability that a randomly chosen person uses both apps, giving your answer as a fraction in its simplest form.

12.Two ordinary fair dice are rolled and the two scores are multiplied together. Work out the probability that the product is odd.

13.On the probability scale from 0 to 1, which word best describes an event with probability 0.9?

14.A jar contains counters that are pink, gold or grey only. The probability that a counter taken at random is pink is 0.2 and the probability that it is gold is 0.45. The jar contains 60 counters in total. Work out the number of grey counters.

15.One card is taken at random from an ordinary pack of 52 playing cards. 26 of the cards are red. Work out the probability that the card is red. Give your answer as a percentage.