Question Video: Using Probability Scale to Describe the Probability of an Event Mathematics

A bag contains 35 marbles, 34 of which are blue. If a marble is picked out at random, what is the likelihood of it being blue?

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Video Transcript

A bag contains 35 marbles, 34 of which are blue. If a marble is picked out at random, what is the likelihood of it being blue?

We can begin this question by recalling our probability scale. This goes from zero to one. If an event is impossible, it has a probability of zero. And if an event is certain, it has a probability of one. In the middle of these, we have a 50-50 or even chance. This is when it is equally likely that an event happens or does not happen. If the chance of an event happening is less than this, we say it is unlikely. And if the chance of an event happening is greater than this, we say it is likely.

In this question, there are 35 marbles in the bag. 34 of them are blue. This means that the probability of selecting a blue marble at random is 34 out of 35 or thirty-four thirty-fifths. This is significantly greater than an even or 50-50 chance. However, it is not certain as one of the marbles is not blue. In order for the probability to be certain, all of the marbles in the bag would have to be blue. We can, therefore, conclude that it is likely that the marble selected is blue.

We could actually go into a bit more detail here and say that it is very likely that the marble is blue. This is because 34 out of 35 is very close to one. The closer to one the probability is, the more likely the event is to happen. For the purposes of this question though, the correct answer is likely.

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