There are 30 pens in a box. 12 of the pens are black.

There are 30 pens in a box. 12 of the pens are black. 7 of the pens are green. The rest of the pens are red. One of the pens is chosen at random. Find the probability that the pen is red. 

A box contains a total of 30 pens, out of which 12 are black and 7 are green. The remaining pens are red. When selecting one pen at random, it is necessary to determine the probability that the chosen pen is red.

To calculate this probability, first, we need to ascertain the number of red pens. By subtracting the number of black and green pens from the total, we find that there are 11 red pens in the box. Thus, the probability of selecting a red pen can be expressed as the ratio of the number of red pens to the total number of pens.

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