In questions in text books and examinations, very often only the needed information is supplied.

In questions in textbooks and examinations, it is usual for all of the needed information to be supplied. In the present example, we don’t have the numbers that we would need in order to be able to calculate the probability.

It is not specified whether the bag also contains other packets of microwaveable rice, or how many red and yellow packets there are.

Nor is it specified whether any red or yellow packets contain something other than microwaveable rice. We are merely told that the packets containing Lemon and Herbs flavour microwaveable rice are yellow, and that the packets containing Tomato and Basil flavour microwaveable rice are red.

what information unknown to the problem solver would influence the answer.

And since you imply that this is not a text books or examination type question, the answer depends also of what the man wants to extract, and whether he is able to look into the bag.

Exactly.

Many people assume at the mention of a bag that it is opaque and that the man cannot see into it.

The man may have in mind which type of pack he wants to pick.

Also, can all the packs be seen or is it a deep bag and all of one type are hidden under layers of the other type?

Even if the man can look into the bag he may decide to have a random choice as he has been making decisions in his job all day and he just wants to have a meal without needing to make yet another decision.

More suggestions for scenarios are welcome.

William

what information unknown to the problem solver would influence the answer.

It is not specified whether the bag also contains other packets of microwaveable rice, or how many red and yellow packets there are.

And since you imply that this is not a text books or examination type question, the answer depends also of what the man wants to extract, and whether he is able to look into the bag.

In questions in text books and examinations, very often only the needed information is supplied. In real life problem solving one often has lots of information available and one needs to decide what is relevant in providing an answer.

Also, what information unknown to the problem solver would influence the answer.

William

In the bag are a number of new, unused, packets of microwaveable basmati rice.

Some packets have contents that are Lemon and Herbs flavour and those packets are yellow.

Some packets have contents that are Tomato and Basil flavour and those packets are red.

A man approaches the bag, puts his right hand into the bag and removes one of the packets of microwaveable rice.

What is the probability that the packet that the man has removed is red?

William