Independent repeated trials

A question is this type if and only if it involves calculating probabilities for independent repeated events (e.g., flights, survey responses) using multiplication of probabilities across trials.

4 questions · Moderate -0.9

2.03a Mutually exclusive and independent events
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CAIE S1 2017 November Q1
2 marks Easy -1.2
1 A statistics student asks people to complete a survey. The probability that a randomly chosen person agrees to complete the survey is 0.2 . Find the probability that at least one of the first three people asked agrees to complete the survey.
OCR MEI S1 2008 January Q3
8 marks Moderate -0.8
3 Steve is going on holiday. The probability that he is delayed on his outward flight is 0.3 . The probability that he is delayed on his return flight is 0.2 , independently of whether or not he is delayed on the outward flight.
  1. Find the probability that Steve is delayed on his outward flight but not on his return flight.
  2. Find the probability that he is delayed on at least one of the two flights.
  3. Given that he is delayed on at least one flight, find the probability that he is delayed on both flights.
OCR MEI S1 Q2
8 marks Moderate -0.8
2 Steve is going on holiday. The probability that he is delayed on his outward flight is 0.3 . The probability that he is delayed on his return flight is 0.2 , independently of whether or not he is delayed on the outward flight.
  1. Find the probability that Steve is delayed on his outward flight but not on his return flight.
  2. Find the probability that he is delayed on at least one of the two flights.
  3. Given that he is delayed on at least one flight, find the probability that he is delayed on both flights.
AQA Paper 3 2023 June Q13
4 marks Moderate -0.8
There are two types of coins in a money box: • 20% are bronze coins • 80% are silver coins Craig takes out a coin at random and places it back in the money box. Craig then takes out a second coin at random.
  1. Find the probability that both coins were of the same type. [2 marks]
  2. Find the probability that both coins are bronze, given that at least one of the coins is bronze. [2 marks]