Minimum of two geometric random variables is geometric [duplicate]

Solution 1:

Use distribution function:

$$P(\min(X,Y) \le x) = 1 - P(\min(X,Y) \ge x) = 1 - P(X \ge x, Y\ge x) = 1 - P(X \ge x) P(Y \ge x)$$

Now compute that and recognise the distribution function of a geometric distribution