Question

В коробке находятся 10 белых 15 чёрных 20 синих и 25 красных шаров .найти вероятность того что вынутый шар окажется 1)белый 2)чёрным или красным

Answer 1

1) 10+15+20+25=70 (шт.) - шаров всего
2)10/70=1/7 - вероятность того, что шар окажется белым
3) 15/70 + 25/70 = 40/70=4/7 - вероятность того, что шар
                                                  окажется чёрным или красным

Answer 2

Given Information

In the box, there are: - 10 white balls - 15 black balls - 20 blue balls - 25 red balls

We need to find the probability of drawing a ball that is: 1) White 2) Black or red

Probability of Drawing a White Ball

To find the probability of drawing a white ball, we need to divide the number of white balls by the total number of balls in the box.

The total number of balls in the box is: 10 (white) + 15 (black) + 20 (blue) + 25 (red) = 70

Therefore, the probability of drawing a white ball is: 10 (white balls) / 70 (total balls) = 1/7.

Probability of Drawing a Black or Red Ball

To find the probability of drawing a black or red ball, we need to calculate the probability of drawing a black ball and the probability of drawing a red ball, and then add them together.

The probability of drawing a black ball is: 15 (black balls) / 70 (total balls) = 3/14.

The probability of drawing a red ball is: 25 (red balls) / 70 (total balls) = 5/14.

Therefore, the probability of drawing a black or red ball is: 3/14 (probability of black ball) + 5/14 (probability of red ball) = 8/14.

So, the probability of drawing a black or red ball is 8/14.

Summary

To summarize, the probability of drawing a ball that is: 1) White is 1/7. 2) Black or red is 8/14.