I am doing some revision for an exam I have tomorrow and I can't work out how an answer is achieved.
The weight $X$ kg of a bag of cement can be modelled by a normal distribution with mean $50$ kg and standard deviation $2$ kg.
$P(x > 53) = 0.0668$
Find the probability, $a$, that two weigh more than $53$ kg and one weighs less than $53$ kg.
So I did: $a = 0.0688^2 \times (1-0.0688)$
However the answer is $a = 3 \times 0.0688^2 \times (1-0.0688)$
I can't understand where the multiplication by $3$ comes from, although three are three bags, surely that has already been taken into account by multiplying $3$ probablities?
(The exam is tomorrow so I would appreciate answers before then, but I would still like to know the answer irrespective of the exam)