Two students each use a random number generator to pick an i

Two students each use a random number generator to pick an interger between 1 and 7.

1. What is the probability that they will pick the same number?


2. What is the probability that they different numbers?

Solution

1. What is the probability that they will pick the same number?

Total number of ways of picking numbers = 7 x 7 = 49

Number of ways one player picks any number = 7

Number of ways the second player picks that number = 1

Hence, number of ways both pick same number = 7 x 1 = 7

Probability they pick same numbers = 7/49 = 1/7

2. What is the probability that they different numbers?

Number of ways one player picks any number = 7

Number of ways the second player picks any other number = 6

Hence, number of ways both pick same number = 7 x 6 = 42

Probability they pick different numbers = 42/49 = 6/7