# Question Video: Determining the Probability of an Event Mathematics

In a class of 50 students, 33 passed the mathematics test and 31 passed the language test. What is the probability that a randomly selected student failed in the language test?

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### Video Transcript

In a class of 50 students, 33 passed the mathematics test and 31 passed the language test. What is the probability that a randomly selected student failed in the language test?

In questions of this type, it is important that we’re able to select the relevant information. We are only interested in what happened in the language test. This means that the fact we are told that 33 students passed the mathematics test is irrelevant. We are told that there are 50 students in total. Of these, 31 passed the language test. Since 50 minus 31 is equal to 19, we know that 19 students failed the language test. And it is the probability of this event that we are trying to calculate.

We know that the probability of an event can be written as a fraction. It is the number of favorable outcomes divided by the total number of possible outcomes. The probability that a randomly selected student failed in the language test is therefore equal to 19 over 50, which could also be written as the decimal 0.38 or 38 percent.