The probability of successful passing of the first exam for a given student is 0.9, the third exam is 0.8.

The probability of successful passing of the first exam for a given student is 0.9, the third exam is 0.8. find the law of distribution of a discrete random variable x – the number of successfully passed exams.

The random variable X can take on the following values:
X = 0 – the student has not passed any exam;
X = 1 – the student has passed one exam;
X = 2 – the student has passed 2 exams.
P (0) = (1 – 0.9) (1 – 0.8) = 0.1 * 0.2 = 0.02;
P (1) = 0.9 * (1 – 0.8) + (1 – 0.9) * 0.8 = 0.26;
P (2) = 0.9 * 0.8 = 0.72.
X 0 1 2;
P (X) 0.02 0.26 0.72;