There are 50 pencils in a pot. 17 are blue, 10 are red, and the rest are green. A pencil is taken from the pot at random. Calculate the probability that the pencil is green.
We are told in the question that there are 50 pencils in total. 17 of them are blue; 10 of them are red. We are told that the rest of the pencils are green. To calculate the number of green pencils, we need to add 10 and 17 and subtract it from 50. 17 plus 10 is equal to 27. And 50 minus 27 is equal to 23. We could work this out by finding the difference between 27 and 50 on our number line. The difference between 27 and 30 is three. And the difference between 30 and 50 is 20. Three plus 20 is equal to 23. Therefore, the difference between 27 and 50 is 23. There are 23 green pencils in the pot.
We are asked to calculate the probability that the pencil selected at random is green. Probability can be written as a fraction. The number of successful outcomes is the numerator. And the number of possible outcomes is the denominator. A successful outcome, in this case, is selecting a green pencil. Therefore, the numerator will be the number of green pencils. The number of possible outcomes is the total number of pencils in the pot. We have worked out that the number of green pencils was 23. Therefore, our numerator is 23. There were 50 pencils altogether. So our denominator is 50. The probability of selecting green pencil from the pot is 23 out of 50 or twenty three fiftieths.