Question

For A level applied maths, I dun get following question marking scheme.
A die know to be biased in such a way that, when it is thrown, the probability of a six showing is 0.25. This biased die and an ordinary fair die are thrown. find the probability that
a) the fair die shows six and biased does not show a six
Ans= 1over 6 times 3 over 4 = 1 over 8
b) at least one of the two dice shows a six
Ans= (1÷4)(5÷6) ×(3÷4)(1÷6)+ (3÷4)(1÷6)
=(3÷8)
C) exactly one of the two dice shows a six,given that at least one of them shows a six (condition probability)
Ans= (8÷24) ÷ (8÷24)+(1÷24)=(8÷9)

Answer 1

a) is correct

b) There are 3 possible outcomes 1. 6 on biased die and no six on fait die, 2. 6 on firs dies and no six on biased, and 3 . 6 on both dies.

you need to check your answer to that one.

Answer 2

* fair (not fait and firs!)