87. Two items worth 5 rubles each and one item worth 30 rubles are being raffled. Formulate the distribution law of winnings for a person who bought one ticket out of 50.
Solution. The random variable $X$ represents the winnings and can take three values: 0, 5, and 30 rubles. The first outcome is favorable in 47 cases, the second in two cases, and the third in one case. Let's find their probabilities:

$$
P\left(x_{1}\right)=47 / 50=0.94 ; P\left(x_{2}\right)=2 / 50=0.04 ; P\left(x_{3}\right)=1 / 50=0.02
$$

The distribution law of the random variable is as follows:

| Values $x_{i}$ | 0 | 5 | 30 |
| :--- | :--- | :--- | :--- |
| Probabilities $p_{i}$ | 0.94 | 0.04 | 0.02 |

As a check, we find $P\left(x_{1}\right)+P\left(x_{2}\right)+P\left(x_{3}\right)=0.94+$ $+0.04+0.02=1$