Question

В магазине канцтоваров продается 118 ручек, из них 32 красные, 39 зеленые, 7 фиолетовых, еще есть синие и черные, их поровну. Найдите вероятность того, что при случайном выборе одной ручки будет выбрана зеленая или черная ручка.

Answer 1

1) 32+39+7=78 (шт.)-ручек красных, зелёных и фиолетовых вместе
2) (118-78):2=20 (шт.) - ручек синих и столько же чёрных
3) 39+20=59 (шт.)-зелёных и чёрных ручек вместе
4) 59/118=0,5 - вероятность того, что будет выбрана зелёная или чёрная ручка
Ответ: 0,5 (или 50%)

Answer 2

Problem Analysis

In the stationery store, there are a total of 118 pens available. Out of these, 32 are red, 39 are green, and 7 are purple. Additionally, there are an equal number of blue and black pens. We need to find the probability of randomly selecting either a green or a black pen.

Solution

To find the probability, we need to calculate the total number of favorable outcomes (selecting a green or a black pen) and divide it by the total number of possible outcomes (selecting any pen).

Let's calculate the probability step by step:

Step 1: Calculate the total number of favorable outcomes (selecting a green or a black pen). - The number of green pens is 39. - The number of black pens is also equal to the number of blue pens, which is half of the total number of pens available. Since there are 118 pens in total, the number of black pens is 118 / 2 = 59.

Therefore, the total number of favorable outcomes is 39 + 59 = 98.

Step 2: Calculate the total number of possible outcomes (selecting any pen). - The total number of pens available is 118.

Therefore, the total number of possible outcomes is 118.

Step 3: Calculate the probability. - The probability is calculated by dividing the total number of favorable outcomes by the total number of possible outcomes.

Therefore, the probability of randomly selecting either a green or a black pen is 98 / 118.

Answer

The probability of randomly selecting either a green or a black pen from the stationery store is 98 / 118.