CAIE
S1
2023
March
Q4
3 marks
Standard +0.3
4 The probability that it will rain on any given day is \(x\). If it is raining, the probability that Aran wears a hat is 0.8 and if it is not raining, the probability that he wears a hat is 0.3 . Whether it is raining or not, if Aran wears a hat, the probability that he wears a scarf is 0.4 . If he does not wear a hat, the probability that he wears a scarf is 0.1 . The probability that on a randomly chosen day it is not raining and Aran is not wearing a hat or a scarf is 0.36 .
Find the value of \(x\).
CAIE
S1
2023
March
Q5
3 marks
Challenging +1.2
5 Marco has four boxes labelled \(K , L , M\) and \(N\). He places them in a straight line in the order \(K , L , M\), \(N\) with \(K\) on the left. Marco also has four coloured marbles: one is red, one is green, one is white and one is yellow. He places a single marble in each box, at random. Events \(A\) and \(B\) are defined as follows.
\(A\) : The white marble is in either box \(L\) or box \(M\).
\(B\) : The red marble is to the left of both the green marble and the yellow marble.
Determine whether or not events \(A\) and \(B\) are independent.