Question

Suppose two dice (one red, one green) are rolled. Consider the following events. A: the red die shows 5; B: the numbers add to 2; C: at least one of the numbers is 2; and D: the numbers do not add to 8. Express the given event in symbolic form.The numbers do not add to 2.

How many elements does it contain?

Answer 1

Part 1

A = {5}

B = {(1,1)}

C = {(2,1), (2,3), (2,4), (2,5), (2,6), (1,2), (3,2), (4,2), (5,2), (6,2)}

D = {(1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (2,1), (2,2), (2,3), (2,4), (2,5), (3,1), (3,2), (3,3), (3,4), (3,6), (4,1), (4,2), (4,3), (4,5), (4,6), (5,1), (5,2), (5,4), (5,5), (5,6), (6,1), (6,3), (6,4), (6,5), (6,6)}

Part 2

35

Explanation:

Part 1

We use brakets for indicate that the elements belong to a event.

In each event, the first member of each parentheses belong to dice red and the second belong to green dice.

We consider in each event all elements that accomplish the condition.

Part 2

When we combinate pair with the two dice obtain 36 pairs (6*6, six possible results in the red dice and six possible results in the green dice), now we look for all of them that do not add 2.

(1,2), (1,3), (1,4), (1,5), (1,6), (2,1), (2,2), (2,3), (2,4), (2,5), (2,6), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)