https://vle.mathswatch.co.uk/images/questions/question15345.png question b onlny
https://vle.mathswatch.co.uk/images/questions/question1073.png
https://vle.mathswatch.co.uk/images/questions/question17645.png
First one
b) Note that 3 numbers are contained in set A and 7 are not in set A
So.....A ' means the elements not in set A
So the probability that a number is not in set A = 7 / [ 3 + 7 ] = 7 / 10 = .7